a mak-90 should of come with wood stocks, should be easy to find at a gun show, the mak90s stock (I THINK) is the only one with a rubber buttpad.
KVAR corp in vegas sells a lot of AK parts, tapco in SGN should have a lot of parts, the nicest stocks are the hungarian SA85.
Ace sells a sweeeet wire stock, definetly worth a look before you buy, but pricey.
pick up a SGN and they should be easy to find, the Mak90 has a STAMPED reciever so you need the correct stock, DONT get the stock for a milled reciever, it WONT fit.
the mak90 is one of the better AKs out there, no reason to be ashamed of it, i WISH i had bought those up years ago.