looks like you need a new flare, so I would check ebay
or local salvage yards. your body shop probably took the price of a new one from the dealership which is about $250 plus. You have a couple of options though. My first suggestions.
Do the body work your self and pay for someone to paint it. If you want to paint then you need to consider a paint gun ~$200, paint~$300, Compressor ~$600 to $1200.
Do the pounding and sanding yourself and pay a shop to spot paint it. Youtube spot repair so you have an idea of the entire process. The damage is low and on the side of the truck which is ideal for spot repairs.
You could also do the body work yourself and buy matching spray pain out of a spray can. It won't look that nice, it won't really help the resale value, but it will be less noticeable, and cheapest option.
Also watch a lot of youtube body repair videos before starting. I don't think you will need to remove any metal, if you can't get behind there to pound out the dents, consider a stud welder or drill holes and get a slide hammer to remove the dents, (just remember to weld the holes up and grind them down before applying filler). Then grind down to bare metal, scuff with 40-or-80 grit, and apply filler. Sand filler with 80 grit. Then I would recommend taking it back to a body shop and getting another quote. it will still cost around $400-$600 or so probably to get them to paint it for you assuming you did the body work correctly.