Canare StarQuad 4s11 is the usual recommendation for a high-quality but inexpensive cable for long runs. It's got four conductors but for non-biwire applications you can combine the two red and two white conductors to create an effective 11 gauge conductor. It's about $1 a foot.
If you don't need cable that large there's 4s8 cable that has four 16 gauge conductors that can be combined to create an effective 13 gauge run.
Go to http://www.markertek.com, type "Canare" into the search box, then choose "Bulk speaker wire" from the middle of the long list of returns in the right column of the search results page.
This question has been asked lots of times and a search of the discussion forums for "4s11" will bring up a lot of information.
If you don't need cable that large there's 4s8 cable that has four 16 gauge conductors that can be combined to create an effective 13 gauge run.
Go to http://www.markertek.com, type "Canare" into the search box, then choose "Bulk speaker wire" from the middle of the long list of returns in the right column of the search results page.
This question has been asked lots of times and a search of the discussion forums for "4s11" will bring up a lot of information.