If you’ve decided to use eBay to get rid of your old camping equipment, chances are you’re not obligated to collect sales tax. These types of one-off sales are known as "occasional, casual, or isolated sales," and are often exempt from sales tax.
States often limit tax exemptions for occasional sales based on the number of transactions or the profit earned within a certain time period. For instance, both California and Texas have exemption limits on resales during a 12-month period.
However, not all states impose these kinds of restrictions. Massachusetts, for example, doesn’t specify a number or amount of tax-free casual sales allowed. As the rules regarding occasional sales vary by state, it’s important to research exemptions everywhere you make sales.
With all that in mind, eBay will automatically apply sales tax to sales in states with marketplace facilitator laws, because the tax responsibility is theirs as a marketplace rather than yours as the seller.