NOT EBAY! Dianna, do NOT buy corsets from ebay, you will just be wasting your money. Those corsets are extremely cheap and not suitable for what you're wanting from them. Try to use them that way and you'll break them just like you did the drug store braces you mentioned. Ebay "corsets" are JUST fashion items. If money is an issue, and, let's face it, it is for almost all of us, check out Timeless Trends. Google it, I don't have a link handy. They're still more than half the cost of paying a corsettier to make you one specially, and they are made by hand by a corsettier, so still of high quality. They are just standardized instead of customized.
EDIT: They are going to cost you a mint though, especially at your size. You've been warned.
EDIT: They are going to cost you a mint though, especially at your size. You've been warned.