I second Dave's answer. Canare makes great, studio-grade cable, and it would be well within your budget. If you're driving the line with a low-impedance unbalanced source, you're likely to have less signal degradation than from a passive, high-impedance source. For relatively long runs like yours, though, balanced interconnects are several orders of magnitude cleaner and more trouble-free than unbalanced. Whenever possible, go balanced.
