Heads-up, eBay is collecting sales tax in several more states

Effective today, auction site eBay is expanding the number of US states where it collects sales tax on purchases by 13, and will add a handful more on October 1. So, depending on where you live, buying an item may have just gotten a little bit more expensive, at least for the upfront cost.

Technically, online purchases are subject to a sales tax the same as offline purchases. Even if a seller does not collect a sales tax on something you buy, you are supposed to let Uncle Sam know and pay it anyway. If you don't, you might get hit with an unexpected bill for past purchases.

For many years, online sites have gotten away with not charging a sales tax, and consumers have not always paid them on their own (shocking, right!?). However, law changes have resulted in this being the exception to the rule. Amazon, for example, collects sales tax in every state, and Newegg is not far behind.

eBay has been one of the exceptions, for the most part. Until today, it only collected sales tax in a handful of states and territories, including Minnesota, Washington, Iowa, Connecticut, District of Columbia, Nebraska, New Jersey, Idaho, and New York.

Now it's adding 13 more, including Alabama, Arkansas, Indiana, Kentucky, New Mexico, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Vermont, Virginia, West Virginia, and Wyoming. That brings the tally to 21 states, plus the District of Columbia.

On October 1, eBay will add five more states, including California, North Dakota, South Carolina, Texas, and Utah.

Sellers on eBay also have the option of charging a sales tax in other states, if they wish. You will often see that when buying from a major eBay marketplace seller, such as Best Buy.

You can find more information on eBay's sales tax policies here.