Subject says it. Roadie frame or MTB? Want a beater to take to the store around the corner and general joyrides. Don't want to use my commuter. Gonna build a SS with a coaster brake only, and a front brake only if I MUST have it.

Any certain equipment to look for? I'll have to had the rear wheel built anyway, I figure whatever I get I'll buy a custom rear wheel for it, as I have NO idea how to build one, though I wouldn't mind trying!

So where do start? How much should I budget for it?