Smallest Windows Install?

HI:

I have a 2007 2.8 GB dual-processor iMac and far, far too often I find myself needing to run some small Windows utility or another, and it's about time I get Windows running on this thing because I haven't any friends who can run these utile for me (and besides, they're only gonna run for a few seconds anyway, so trucking to someone's apartment to do something that'll take mere seconds is dopey anyway).

I'm a disabled vet and can't afford anything, pretty much, but I need to compose a shopping list. Wouldja help me with it, please?

- A small hard drive to hold Windows (how small, exactly?)

- a copy of Windows (which version? Can I get away with XP? Which version, zactly? Cheapest one, please, please,)

- a copy of Bootcamp (I don't already own this in a Utility folder somewhere, right? I know I don't have my original install disc from 2007. It's long gone.)

Before you ask: yes, I absolutely hafta run Windows sometimes when there's no analog Mac software. You know how it is.

I just want the barest minimum Windows install that'll get the jobs done. I don't wanna run Office or any such nonsense. I just need to run little **** utils now and then. And I wanna emphasize that any money I spend on this project is gonna hurt, so please don't go suggesting that Kinja has a deal on a 2TB portable drive right now and so on. I'll cry.

thanks for helping with this. I appreciate it a lot.

BInky