Well, I can answer one question regarding mags and drums.
Pretty much any mag will do with an AK, unlike AR's. They're pretty much all the same quality and all will work well.
With drums, either type will do. The only difference between the Chinese and the soviets is that the Chinese loads from the rear and can be stored with the ammo inside, as there is a lever you wind-up on the back to put on spring tension. Average price for one of these is $100
The soviets (or romy) drums load one at a time from the top, and shouldn't be stored very long with the ammo inside, because it always has spring tension unlike the wind-up chinese. Average price for one of these is $75.
As far as a source for magazines and drums, contact RONIN45 on the EE board. He's selling 40 round mags real cheap and 75 round niw Romy drums for $55 + $4 shipping. This is the best price for drums anywhere. Don't expect an instant response from him though, he's not a dealer and is real busy with other stuff, but he will get to you. His prices are worth the wait.