For comparison, mine is in the shop now having all 18 control arm bushings replaced, new upper and lower ball joints installed, stainless steel brake lines installed, rear sway bar links replaced, rear toe links replaced, rear knuckle bushings replaced, rear wheel bearings replaced and DTML pump replaced.
I expect total for parts/labor to be roughly $2,500.00 plus an alignment at the dealer.
As mentioned above, find a different shop.
If you are handy, at all, you can also swap those struts yourself in your driveway in about 30-45 minutes per wheel. Very easy job. Requires 3 or 4 tools and a jack to get the wheel off the ground.
ETA: Also, it is probably unlikely you really have a strut issue. These things just don't fail that often. I would recommend raising your truck to offroad height one evening. Take a careful measurement from the lower wheel arch molding to the centerline of your hubcap and record your results. Take the same measurement 8 or 9 hours later after sleeping for the night. If those measurements are equal, don't worry about the struts.