I've done a lot pf papier mache, and have never done anything on the stove!

Cheapest, easiest thing is a 1 pound back of powdered wall paper paste from the paint store (really cheap! Might be $1.00?).

I start with a bowl of warm water, and add the powder a little at a time, stirring to keep it smooth, until it's the right consistency. Has always worked well for me.

The number of layers depends on the item. At the very least, I use 2; if I want the item to be (or it needs to be) really strong or durable, I'll do 4-5.

Hope this helps!