I was looking for prices of sets. Here ya go:
SK 7-19mm 3/8" $66
Proto 7-19mm 3/8" $85
Williams 3/8" $40 (undoubtedly Asian imports)
So here's my advice:
1) First have a look at this gentleman's post:
http://www.garagejournal.com/forum/showpost.php?p=4327566&postcount=9
Notice the difference in size between the Snap On 12mm and the other sockets. This is one of the reasons so many of us recommend Snap On. And not only are these sockets thinner, I believe they are harder and stronger as well. This may be a feature you need or it may not be.
2) I believe Snap On places the detent balls on their extensions and ratchets in a slightly different position from other makes. Their sockets have divots designed to work with their drive tools. Consequently, craftsman sockets fit more loosely on Snap On ratchets and extensions. This looseness varies between imperceptible, to minor annoyance, to major pain in the ****, depending on the drive size, extension, etc. If you think you are going to someday want Snap On ratchet handles or wobble plus extensions, I think you'll do better with Williams or Snap On sockets. They are part of a system designed to work together.
3) If you look at used Snap On prices on ebay, you can usually find like new socket sets in almost any size/drive for under $100. That's more than these other sets, but not loads more. I have bought 1/4" drive sets for as little as $50.
Not trying to talk you into to anything, just offering suggestions and options and things to think about. When you look at some of the issues above, you can see why some of us greatly prefer Snap On even if we are not pro mechanics. I only have a few sets of Chrome hex sockets (2, 1/4" shallow and semi deep, 3, 3/8" shallow, semi, deep - I also have the **** low pros - 1 set of 1/2" drive). So I may well have paid double or triple what you can get other brands for. I may have paid $300 more than other people for my Snap On sockets. That doesn't break my bank. But - Snap On makes sense to me and for me. It may not for you and your work.