Corsets are everywhere and some are incredibly affordable but you need to know that sometimes a deal is not a deal, and that is often the case with corsets. It's easy to find a corset for a Halloween costume but getting one that will realy shape you, hold you and support you is alot more of a challnge and if that's what you're looking for then having one custom made is the best option.
Farthingales offers tips on how to work with a corset maker and they have a list of corset makers as well. Check out the link below for more information.
http://farthingalescorsetmakingsupplies.com/tips.php?article=63
All of the corset makers on the list have used Farthingales quality corset making supplies.