Cheap way to catch up on Battlestar Galactica season 3?

Any thoughts on a cheap way to see season 3 of Battlestar Galactica before season 4 begins? My usual route, the public library, won't get it in time. I could join Netflix or Blockbuster (I plan to sometime anyway) but I figure I'll get stuck at the end of a long line. Could buy it on Amazon for $39 and sell it back to the local video store, but they'd only give me $12 for it - net cost $27. If I watch the last 5 episodes online, I'd presumably only have to rent 4 of the disks at the local video store (?) which comes to maybe $18. I'll do the last if I can't come up with anything else, but any other cheap, legal alternatives?