A big part of the reason I bicycle is for environmental reasons.

Thus, I try as much as possible to use old discarded tires. Yes, this limits my wheels to 27" or 26" and I don't get the performance of some of the newer tires, but I put up with it. Some of the tires I get are really nice, some were never good - it is pot luck. Anyway, I put on enough bike miles that I eat-up tires. Perhaps unlike many of the readers of this forum, I have a big supply of old discarded tires which makes them affordable and convenient as well.

When I am fixing a bike for someone who needs 700mm tires or wants something special, I usually get them from the LBS. This is because the price is almost the same as if ordering on-line once you factor in shipping.

I noticed that not LBS are created equal. One LBS here charges twice as much for parts and service as others. Still, they do a lot of business despite there limited knowledge high school student minimum wage staff (who have plenty of wrong and bad advice if you need some).

It pays to shop around for a good LBS if you have that option where you live.