The requirements for AFP are not high at all.
Heres my system:
AMD T-Bird 1GHz
384MB of DDR 2100
GeForce 2 MX400 32MB

This computer runs AFP on 1024x768 and high texture at a constant 50 FPS (with smoke at all times). It never lags. You can buy a system with these specs for around $500 and even less if you have a monitor and can build it yourself.

You dont have to go and spend $200+ on a video card unless you want to play more advanced games.

Do you have a computer now? What are the specs?

EDIT: Just saw you wanted a laptop. If this is the case then you are going to be spending around $1200. Be sure to get the new Intel Centrino and a video card with at least 64MB (the video card memory on a laptop is shared with the monitor so you need more). Anyway, you can see from my specs what you basically need.