Local mechanics getting TRE at NAPA or the dealer or wherever they pay wholesale and then charge you retail, are making money off you two ways. Shockingly, GM list price is $190-200 per side for the outers, and $150 for inners. I buy European (not Chinese) aftermarket units for $30-40 each. And many of us have changed broken outers on the trail in 10-30 minutes without even removing the tire. If the mechanic is not including an alignment, then those prices are ludicrous.
Enough to push a reluctant person into becoming a DIY mechanic, even.
Any reason that isn't an option? $500 would buy a heck of a starter set of tools.