You can try here:
Austin Amateur Radio Supply
5310 Cameron Road
Austin, TX 78723
800.423.2604 • Local 512.454.2994
I've heard they do CB stuff, but haven't personally used them. An SWR meter is only about $30, and tuning is easy. They are available at any good truck stop. You'll also need a 3' coax cable. Amazon, etc, also carries SWR meters.
Tuning is especially easy if you have a tunable antenna - like a Firestik with the screw knob on top.