Mavis Tire went in with a coupon for oil change and tire rotation ($21.99 - issued by Midas but accepted at Mavis!); was told I needed front brakes and power steering fluid, and some other things I didn't understand Internet

I had a ShopRite coupon for Midas for an oil change and tire rotation ($21.99), but wound up at Mavis instead, who graciously said they'd accept the terms of the coupon.  After waiting for about an hour I was told by the service manager that I needed not only front brakes (he said it was metal-on-metal) but power steering fluid and some other things.  Instead of paying $21.99, my total bill was $477!  Note: I had my car inspected 2 days prior, and there was no mention of my needing brakes, nor did a light come on my dashboard saying my brakes were bad (Monday morning quarterbacking by my well intentioned friends).  I called the inspection station and was informed that the problem with these "coupons" is that they are designed to lure customers in and convince them to have unneeded work performed.  Being a single female, I fell for it (I am ashamed to admit); but I was also making a long trip the next day and was afraid of my brakes or power steering go, so acquiesed to their diagnosis and price... much to my chagrin!  My warning to others: insist on a 2nd opinion, or take it to your regular mechanic or dealership!  I learned my lesson the hard way!