If you have already put 7k into the car, don't dump more. I would trade it out and move on. It is 15-16 years old with enough rust a mechanic has warned you. Body shop work is really expensive now. Reputable licensed shops can't cut corners parts costs are way up so is labor.

 

PA is very strict on body rust unlike NY where flapping fenders are OK.
Time to get rid of it unfortunately. At least it's not bad enough yet so they gave you another year. If it was unsafe they would have not gave you a sticker.
I lived in the PA, NY and NJ tri state area for years so I'm savvy to the inspection rules.

 

The $7k that you already invested in the car does not factor into your decision. It is no longer your money. Similar to playing poker. You cannot make your decision to stay in the pot because you already have invested $x amount of money. That money is gone !

 

You could ask a local voc tech high school if they wanted a project for the kids. It would cost significantly less than a body shop just so you can pass inspection.

 

Invest the 10K in a newer vehicle. Time to trade. 👍

 

Rust is often blown out of proportion, especially by mechanics and body shops. The car will drive for years with gaping holes as long as the structural elements are sound.

My suggestion would be to find a backyard body shop or rust repair specialist to repair the car, 10-15k is far too much for rocker panels. The problem is there's a lot of guys that don't know what they're doing and will only cover up the rust to get it past inspections. References would be required when shopping for the correct shop. If you're close to NJ I would recommend Outlawed Specialties in Newton.

 

5000 miles in 4 years indicates you don't drive it much. Keep driving it until they won't pass it. You'll get at least one more year of it. Next year I would try a different shop. They may not be so strict. Put the $10 K in the bank and then go shopping for something different.

 

Now you know why car washes have that underbody spray when you enter the wash bay.