Why don't you make you own? There are a few DIY suppliers out there that will sell you the parts although I am not sure how much the end product will end up costing vis-a-vis your budget.
An alternate choice would be to buy a contractor grade (I think they are a minimum of 12 gauge) extension cord and install a male IEC end on one end. I think that as long as the gauge is large enough and the insulation is there something like that should be more than sufficient to get the juice to a subwoofer. Probably cost you $50...