Most legitimate US-facing online stores aren’t trying to sidestep sales tax. They’re applying whatever each state requires based on where you live, where the seller has “economic nexus” (enough business activity to be taxed), and whether the product itself is taxable. That’s why you’ll see one cart with sales tax added and the next one with none. It usually reflects different rules, not secret tax evasion.
States rely on sales and related taxes to help pay for roads, schools, and health programs, so they’ve tightened rules for online commerce. After the South Dakota v. Wayfair Supreme Court decision, many states gained authority to make remote sellers collect tax even without a physical store there, as summarized in analysis from the U.S. Government Accountability Office.
As a buyer, that means you should expect tax on more online orders than you did a decade ago. As a small ecommerce seller, it means you can’t assume that shipping across state lines lets you ignore tax—especially once your sales grow.
How US E‑commerce Sales Tax Works and Why Some Orders Show No Tax
US sales and use tax is set at the state (and often local) level, not by the federal government. Each state builds its own rules for when an online seller has to collect tax and send it in.
Economic nexus in plain English
Historically, states could only force you to collect tax if you had a physical presence there. Wayfair changed that. Now states can base nexus—your taxable connection to the state—on economic activity, not just a warehouse or office.
In practice, that means:
- If your online store has enough sales or transactions into a state, that state may require you to register and collect its sales tax.
- The thresholds and details vary by state, so there’s no single nationwide rule. Guidance from sources like Thomson Reuters stresses checking state-by-state rules.
For buyers, the key is simple: a store that has nexus in your state should generally be charging you that state’s sales tax on taxable products.
Why you sometimes see $0 tax at checkout
A zero-tax cart doesn’t automatically mean the seller is cheating. Common legitimate reasons include:
- Your state doesn’t have a general sales tax. Some states rely more on other taxes and don’t levy broad state-level sales tax.
- The seller has no nexus there yet. A very small or new seller may not have hit your state’s economic nexus trigger.
- The product category is exempt or reduced-rate. Some states treat groceries, clothing, or specific items differently.
- You’re technically responsible for use tax. In many states, if a seller doesn’t collect tax, the buyer still owes “use tax” on untaxed purchases. States like those discussed by the National Conference of State Legislatures are increasingly reminding residents of this.
You’ll also see differences between physical and digital goods. As coverage on FedLaws shows, more states are starting to tax digital products (software, streaming, downloads), but the rules vary widely.
The link to state benefits
Sales tax isn’t just a line item; it feeds into your state budget. According to analysis from the GAO, expanded remote sales tax collection has helped states support services like transportation infrastructure, education systems, and health-related programs, among others.
You don’t see that at checkout, but every compliant transaction is one small piece of keeping those systems funded.
Platform Models and Their Typical Approach to US Sales Tax
Different ecommerce platforms structure their tax responsibilities in different ways. That’s why buying the same product via a large marketplace, a hosted boutique, or a cross-border marketplace can feel different.
Common platform models
Here’s a simplified comparison of how major model types typically handle sales tax:
| Platform model | Who you buy from | Typical tax handling pattern* |
|---|---|---|
| Large US marketplace | Third-party sellers plus marketplace retail | Marketplace often calculates and collects tax for many states on many orders. |
| Hosted storefront | Individual brand or small retailer | Store owner configures tax settings; platform provides automatic rules by buyer location. |
| Digital‑only platform | Software or digital-service provider | Must track which states tax digital goods and apply location-based rules when charging buyers. |
| Cross-border marketplace | Overseas suppliers | Platform or seller may or may not collect US sales tax; buyers can still owe use tax and duties. |
\*Patterns are generalizations; always check specific platform and state rules.
Discussions on platforms like Shopify confirm that US-focused storefront tools commonly use automatic tax rules tied to buyer location, with options for overrides and exemptions when you need to customise rates or handle special products, as seen in the Shopify Community example.
Physical vs. digital sellers
If you sell physical goods from a warehouse, your nexus picture may include:
- Your home state (physical presence)
- Any state where you store inventory (for example, in a third-party fulfillment center)
- States where your sales volume crosses economic thresholds
For digital goods and services, the challenge is knowing which states tax them at all, and how. Some treat streaming subscriptions like taxable services, some tax software downloads, and others don’t. The FedLaws overview highlights how this expanding “digital tax net” can complicate compliance for platforms that sell non-physical products.
Cross-border marketplaces and embedded taxes
Cross-border marketplaces connect US buyers to suppliers overseas. Because those suppliers are taxed under their own country’s rules, the price you see may include relatively low local taxes or none at all on the supplier side.
That doesn’t cancel US obligations. You can still face:
- State sales or use tax on your side
- Customs duties and import fees when goods enter the US
Platforms in this category include options like DHgate, which acts as a marketplace for mainly China-based sellers. Its pricing can look lean partly because supplier-side taxes and local fees are different from US retail. If you use a marketplace like this for sourcing, treat US tax and import handling as your responsibility unless the seller or platform clearly and lawfully collects it for you.
For more context on marketplace structures, you can read What DHgate is and how the marketplace works or compare it to broader online marketplaces and shopping platforms.
Choosing Platforms and Tools That Keep You Realistic About Tax
You don’t need to become a tax lawyer to run a small ecommerce business or shop smartly online, but ignoring tax because it’s annoying is risky.
If you’re a US buyer
For everyday shopping:
- Expect major marketplaces to charge sales tax when they have nexus in your state.
- Don’t assume a $0-tax cart on a smaller site means the transaction is “tax-free”; you may still owe use tax depending on your state.
- Factor the true landed cost into your decisions for cross-border orders: product price + shipping + expected duties and, where applicable, your state’s tax.
If you’re a small online seller
Typical practical steps:
1. Start with your home state
Register, collect, and remit sales tax where your business physically operates once you cross your home state’s trigger for requiring registration. Use your state revenue department’s guidance or resources like Thomson Reuters’ ecommerce tax overview for context, but rely on current state rules for decisions.
2. Leverage platform tax tools
Hosted storefronts and many marketplaces offer location-based tax settings and automatic rules. These tools won’t guarantee compliance or eliminate audit risk, but they can reduce manual rate lookups and help you apply the right rate to most everyday orders.
Whenever you change product lines or start selling into new regions, revisit your platform’s tax settings and your state guidance to keep them aligned.
3. Watch your sales footprint
As orders grow into other states, periodically check whether you’ve hit any economic nexus thresholds. Many sellers use third-party sales tax software to help track this and automate filings. Software can be useful, but it still needs to be configured against the specific rules of the states where you do business.
4. Keep clean records
Whether you sell via your own store, a large marketplace, or cross-border marketplaces, detailed sales and tax-collection records make audits and corrections far less painful. Good records also help a tax professional quickly spot gaps or errors.
If you plan to source via cross-border platforms like DHgate and then resell to US customers, be realistic: lower supplier-side tax doesn’t remove your duty to handle US sales tax correctly on your resale.
Tax rules change and differ by state. This article is informational, not legal or tax advice. Before making registration or collection decisions, check your state’s current rules or speak with a qualified tax professional.
Sources:
- Sales and use tax guidelines for e-commerce retailers – Thomson Reuters
- Remote Sales Tax: Initial Observations on Effects of States’ Expanded Authority – U.S. GAO
- States adapt tax laws as online sales surge – NCSL
- Sales Tax on Digital Products and Streaming Services – FedLaws
- Shopify Community – Why are some customers not being charged tax on my online store?