Not many floating around any more. Dealers are wiped out of kits-- Best bet is to check Gunbroker, AR-15.com, Akfiles.com, theakforum.net, or the likes for individuals selling on the classifieds. They show up a lot more frequently on those sites as specialty boards than somewhere like here at THR which is a more general firearms board-
As to price, better sit down if you haven't checked in a while. They have shot up-- long gone are the days of $100 parts kits, now you are lucky to find one sub-$300
Romanian G kits are now running around $300
Yugoslavian M70 kits are running around $400-450
RPK kits (Yugo) are running around $400-500
AK-74 kits are running around $600-800