Any of the online / mail order places do inner tubes. I think by us the local bike main dealer charges £10 to fit you loose tyre to a loose rim, but of the 3 tyres I my dad and a friend had fitted they got them all fitted wrongly with the result of 3 blowouts. I now fit my own. I do occasionally pinch a tube resulting in having to use another but even then it's faster and cheaper. With prectice you'll get to the point where even landrover and dumper tyres don't phase you - I fitted my own set of 4 dumper tyres to our landrover a couple of years back for that bit of extra traction. On a 550 wheel all you'll need is 3 x 6 inch tyre leavers and a footpump to inflate the tyre. For bigger stuff a big vice to brake the beads is handy. The first tyres I ever fitted other than pushbike ones were to my 550.
