I wouldn't trust most shops around here to know how to glue a tire, and if you can't do it yourself then $22 is worth it to be safe... if you can trust the shop, and Incycle is one of the few shops around here I think can properly glue a tire (Open Air is the only other one that comes to mind). Then again, I learned how to do it myself and did it for free. Messy, but I never rolled a tire.

By the way, does the $22 include the glue? That's like $6 of it right there. If it doesn't and you don't like the price, learn to do it yourself. It's not that hard, but shops probably charge a premium because (a) they know few other shops are willing to do it, and (b) they run a liability risk every time they do it.