Showing you how to put up a tent isn't the same as showing you how to adjust your brakes. The tent salesman isn't going to show up at your campsite and assemble your tent for a small fee, but you will bring your bike in for brake adjustments, now and again.
The co-op is a good option, if there's one near you. You can learn, and practice, with supervision.
Also, REI stores sometimes offer bike maintenance classes for free, or for a reasonable fee, so that may be another option.