RepairPal Certified shops can diagnose and repair your 2005 Chevrolet Equinox. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
The way to do it cheaper is to buy the $12 part(s), and do the work yourself. Gaskets are not expensive, but labor is not cheap. Sorry not to have a better answer, but the truth hurts.