I just bought five Sumitomo 185/70/13 tires from USA Express. They got new tubes for me, but I don't know where they got them. I could ask if you can't find them.
I tried SS and British Wire Wheel for liners, but no one had them. British Wire Wheel told me to use a heavy mil (double the standard thickness) electrical tape available at some hardware stores. Also advised against Duct Tape.... They suggest two complete wraps around each set of spokes. Very helpful folks at BWW.
So, I found the tape, and the tire shop installed it, tubes and tires as well as balanced them. The whole job cost me about $435 and they sure feel good.
Side note... the old tires had packing tape for liners, one tube had a hole in it but there was enough of a seal with the bead and the packing tape that it hadn't leaked. One of the tubes tore the valve off.... rotten rubber.
No telling how long those tires had been on the car..... The outside showed some cracks in the rubber, but didn't look nearly as bad as they were. Fortunately, I only drove it very local. If I had known how bad they really were, I'd have not been driving on them at all.
Rich