Lowes sells speaker wire cheap by the foot. I bought 12awg wire for about 35-40cents/ft. ......16awg wire is a lot less....
As for connectors......... it can be pretty tedious connecting speaker wire of any thickness to some receivers because of shielding around the binding posts. It seems that all many receivers give you is a tiny hole in the shield to cram the wire into and it's difficult to get the wire nicely around the post
For that reason, I use banana plugs in the back of the receiver because 'jacking in' is much easier and a good connection is assured. I connect bare wires at speaker end.