Cheap Body Panels?

For floor pans save your money and buy the cheaper ones. Unless you need a full pan then your stuck going with AMD. Go with the better quality for the quarters. However, I dont think AMD sells skins anymore, just the full quarters. Do NOT buy cheap trunk extensions, they are junk. Even the AMD ones require some fitting but some of the cheap ones fit so bad its ridiculous. The AMD ones usually only require very minor work and sometimes none at all.
For AMD stuff I go straight through AMD. Search around on auto body specialt's website for the cheaper panels. Buy Auto Body Parts Online | Autobody Specialties
I have found the inner fenders are accurate and fit well no matter where you get them. The AMD ones are slightly thicker than the cheap ones. Not enough difference to worry about though.
If you end up doing outer rockers, wait and do them last after you get some experience. Locating them is critical.