buy a 14 awg speaker wire then an rca connector and you are all set. I initially thought of using an ordinary rca cable and cutting the other end to connect to your AVR but I don't think you can find an rca cable long enough for surrounds, also it is better to buy a decent speaker wire so that you can use it when you install a better surround speakers.
when I bought a sub woofer cable and an rca connector at listening room, they had it (the cable and the rca connector) connected free of charge.
hth