Or perhaps renting one from flexshopper.com would make it doable for you?
Here are some links to drives you can pay to keep a few weeks and then return.
USB 2.0 Drive #1(LG)
USB 2.0 Drive #2(OWC)
USB 3.0 Drive #1(Buffalo)
I have not done this myself, so I cannot say whether or not it’s a good idea, but it’s an idea.