Let's face it, film isn't cheap these days and processing (although not megabucks) can be variable to say the least. As I can neither make film not process it (just yet) I have no option other than to pay for these privileges. However, my experience of having a lab scan my negs was not a happy one. 
The better labs quote prices way higher than I'm prepared to pay to scan individual negs to an acceptable size and in TIFF format. "High Street" labs tend to offer batch scans at low / medium resolution and in JPEG format. The latter is, IMO, false economy as they lose a lot of detail, tend to over sharpen images and set contrast too high.
If you use a lot of film on a regular basis, it is worth considering buying a decent scanner. There are a number of good 35mm scanners out there or, if you use MF / LF film, an Epson V700 / V750 can make a good purchase. I have the V750 and it's more than paid for itself given the amount of film I use (waste) and I get to scan and re-scan until I get the end result I'm after.