well to be honest I think the most simple and best way is to get a hard drive. Just something like 20gb would be good. Though I don't know if they sell hdd's with such a low capacity anymore, but you should find some at ebay or some other similar service.
Or then just get a 40gb one, for example this
it's not that expensive, but of course ebay or something will be cheaper. (especially if you can find a 20gb one)
And if you go with the hdd in the link above, just remember that it's OEM so it won't come with any cables etc. But since the mobo is retail it should come with a few ide cables.
And if it doesn't you can get an ide cable from a local store for like $2.