SharBear...I think you have a great chance of doing fine, and getting that one vacation a year! One thing I do want to mention, is beware of buying and selling. You generally are all right, if you are buying your childrens clothing, and reselling on eBay. You often are not making a profit doing that (but it sure beats the .25 from a garage sale!)..you seldom get more for used clothes than you pay for them. However, what you are talking about doing now, is running a business. Buying new and reselling. Although you seldom hear of someone getting "caught", technically, you are running a business. You may owe income tax on your first dollar, if you have another job, or file with your spouse.
I have an actual business, so I file a schedule C and take my expenses off there. If you file misc income, you actually end up paying more taxes (versus Schedule C). The only people I personally know that have been "caught" have been people who were either traced via "bragging" on a board (usually an eBay board, and posted their eBay site, which leads to their real name in contact info..it's a very competitive business), or reported by a jealous friend. So, I would recommend, if someone is going to go "gung ho" on selling on eBay, and reselling items (not your own used items) you keep this in mind : )
Just an aside.