I do not like to suggest Western Digital green drives, however, you indicated that you were short on cash, or something like that. Probably the reason that you could not find info on speed is because it changes speed.
After I wrote the above sentence I looked this up for you on WD's site. For some reason it was a pain for it to get started at my end, so I stopped it and re-started, no problem with the download after that. Here is the link to the PDF:http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701250.pdf
Western Digital Black are the best, followed by Western Digital Blue, WD Green is a distant 3rd, and can be replaced by a different brand.
This is the drive I would put in the computer if it were mine, and needed a small drive:http://www.newegg.com/Product/Product.aspx?Item=N82E16822136770