Depends whether you want a 'heavy duty' corset or an easier option. I got a 'heavy duty' version from Mama1010 (i think that is the name.) they have a counter within Toys R Us in TST. You can get the full set (3 pieces, the body which cinches in your upper body, the waist corset, and a bermuda 'spanx like girdle). You only put it on after your wound has healed (if you have a c-section), the hospital will provide a standard elastic type girdle a few days after giving birth. Spanx was a great option when the weather is hot and when you cannot be bothered with the heavy duty girdle.
Basically all girdles work well, as long as you wear it. Many of my girlfriends bought many fancy girdles and only end up wearing it a couple of times as they found it too hot and stifling.