try www.phoenixent.com
Phoenix Enterprises product listing WIRE & CABLE - BULK
100' roll 10 conductor $15.90 vs 100' roll 6 conductor $30.80 (Polyolefin (PO))
(PVC) 300' roll 6 conductor $40.72 Poly-Vinyl Chloride (PVC)
so I guess it depends how long a length you want and if don't mind peeling off 4 wires.
same here
http://www.mpja.com/9-CONDUCTOR-FLAT-CABLE-100ft/productinfo/8566+WI/
100' roll 9 conductor, $16.95. Buy 5 for $13.95 each (PVC)
All seem to be 28 guage made up of 7 strands of 36 guage
I don't know how Jacket (Insulation) Material compares: Polyolefin (PO) vs Poly-Vinyl Chloride (PVC)
Polyolefin gets you down to -40C vs -20C for PVC.