Q: In 2003, I started a sideline business selling items on eBay. If my regular salary at work exceeds the Social Security tax wage base, do I have to pay self-employment tax on my eBay earnings? S.J.S., via e-mail
A: Yes, that's correct. The self-employment tax rate is 15.3 percent on the first $87,000 of earnings in 2003, then 2.9 percent on amounts above that. But the Social Security tax paid on your employee salary is credited to you for that purpose. So you'll only owe a 2.9 percent self-employment tax rate on your sideline business income if your salary from your regular job was $87,000 or more.