If given the choice, buy the cheapest possible 1/4 inch set. You won't need it for anything requiring large enough torque to matter. This is presuming that the 3/8 and 1/4 inch set is not almost the same price as the 3/8 set alone--many times they are similarly priced in casual experience.
As to using adapters to make sockets and wrenches of a different size work... if you're turning anything that's really tight you'll break one or the other. Typically you don't need to keep 2 full sets of 3/8 and 1/2 sockets--get as little overlap as possible. The adapter that goes from a 1/2 inch wrench to the 3/8 inch socket is likely to break before the socket will, in my experience, due to it's shape. But the point is use the adapters only when you absolutely need to. Sears sells individual sockets if you have a special job and only need one tool.
For the bigger bolts/nuts, I've found that the air tool sockets fit tighter (and are therefore less likely to round your fastener's head). They're also harder so less likely to break. But they do cost more.
My main tools include... Combination 1/4 and 3/8 socket set having some long sockets too, in both metric and English. I got this for about $50, 10 yrs ago. a set of 14mm-22mm air tool sockets $40 around, 4 yrs ago.
18 inch 1/2 inch non-ratcheting socket wrench around $30, 8 yrs ago.
All Craftsman, but that's what I could afford. Beware of single store tool warrantees that require you to bring the receipt back with the broken tool and/or mail the broken tool somewhere for replacement. The $10 complete socket sets are ok if you don't have to use them for anything strong, but you'll eventually not be able to resist temptation because it's close and the better tool is not as close, resulting in a rounded nut, broken tool, etc.
Great neck tools seem pretty good to me but they don't have the great no questions asked, any Sears store warranty. Husky at Home Depot has a warranty similar to craftsman, but looking at the home improvement mega store business's track record it's unlikely Home Depot will be still around 40 yrs from now (in the Cleveland area we've seen at least
3 major chains die in the last 20 yrs and now Lowes and Home Depot are duking it out)