I'm interested in building a computer (cheapest parts) that will be the cheapest for mining (not it's solo purpose). I would also be using this as a regular computer, but would like it to be expandible in the near future (expand number of gpu cards). Any suggestions on what graphics cards will go with a good motherboard for the cheapest price? 
If you want to mine bitcoin certainly requires a sophisticated computer because you will be competing with the other computers in the same mine bitcoin as well. the suggestions I've made more than one computer, the result is very little