Are all Fets the same?
 

Looking on ebay at FET's and some are expensive and some cheap. If I lookup MOSFETS they seem real cheap. Just wondering what are the differences?

http://www.ebay.com/itm/AF4502C-P-N-...item4ab1500604

unfortunately all fets are not the same, there is several different types, and each type may vary in one way or another. whether it be a different channel, spec, or whatever.
they can have different internal resistances, different voltage rating, amp ratings, so in a nut shell get something thats been tested / recommended for the proper use.

for evos
this
or
this

I buy FETs from the manufacturer. Send me a PM if you need a few.