I can’t comment on the bamboos other than to say you might get a Wacom Intuos 3 on EBay for a pretty low price, or via using an educational discount.
As far as the file sizes go, the DPI doesn’t really matter at all, it is just the pixels that matter. Your detail image needs to be 240x240 and your shirt placement needs to be 580x580. If either of these has a different dimension than those, then that image will show up blurred on the voting pages, because woot will compress it to that size.
The print-ready file, of only the design, or only the ink that will go on the shirt,with its separate layers for each color, is supposed to be 300dpi, no larger than 16"x20". So, see, you actually need 3 files.
Thanks! I will look on ebay for that and thanks for the help with the file sizes. I was thinking for some reason that my print ready wasn’t the right size, but i haven’t heard anything back saying it’s not, so it must be alright.