You can get good basic speaker wire at Lowes or Home Depot. Just look in the audio/phone/computer wire section and go for a roll of any copper wire between 12 - 16 gauge. The longer the run, the lower the gauge number, but 16 gauge is rated as fine for up to 50 feet.
If you choose, you can get terminators", either banana plugs, spade lugs or pin connectors there as well but bare wire will work fine. Just make sure there are no stray wires that could cause a short. Amps don't like them at all.
To put Mike's mind at ease, you can use the same kind of wire for both the right and left speaker.