Believe it, or not, parts prices at some dealers, is very competitive, and a lot of times, could beat the others.
It's all depends on a particular location. In a coarse of my O/O career, i was able to find a few!
Not all truck dealers are crooks, some of them are very professional, and honest.
Notice, i didn't say "cheap", but you'll still get a good value, for their services.
For anything, a little more serious, than the tire, or oil change, i go to OEM dealer, which use to be Volvo, and now it's KW.
Since my engine always been "yellow", it's a CAT dealer for that.
When i find that place i like, i try to establish a good relationship with it. we are on a first name basis, which helps a lot.
Shop around, but when you find a good one, within your lines, stick with it!
Don't assume, that if they got the same name(KW, CAT...ETC) they are all the same, people, who works there, makes all the difference! 8)