Will a battery grip made for the Nikon D3100 work on the D3200?

I think I'm going to purchase a Nikon D3200 soon and one of the first things I want to get for it is a battery grip for extra power. However, with it being a brand new camera there are no accessories made for it as yet. I'm looking into a cheap third party one from eBay but wondered whether a battery grip that says it's for the D3100 will work in the D3200?

No.

Nikon never makes a grip for this level of camera. Therefore they feel free to change form factors and a new grip will just not fit.

Additionally, grips like these always use weird constructions to get the button to function. If it's purely for extra power just get a second battery, changing one will take 10 seconds at most.

Nope. Grips don't give you extra power - If you have two batteries, then you have two batteries - the camera only uses one at a time.