I did the math and for the amount of color film I shoot and the cost of the chemicals and the keeping properties of them, it didn't make sense to do it myself when I have a Costco right down the road.
Scanning is a different matter; their scan CDs are $3 at time of development, but they're not particularly high-resolution. Perfect for web and smaller prints, maybe up to 8x10; 11x17 would be pushing it.
This is all moot if you shoot a lot of color film or shoot formats other than 35mm; Costco will only do 35mm. They may or may not have the ability to do larger formats, and they may or may not be able to provide higher resolution scans, but they don't.
I have them develop my film then I take it home and scan it and store it in negative pages.