well, it depends what are you going to do. For single thread programs 6350 will perform better, in gaming about the same ( i'm talking about this gen games like BF3, metro 2033 and older. Don't know about upcoming ). For video editing 8320 will perform much better. So it is your decision.
By the way looking future proof 8320 is best CPU for the money because upcoming games are going to maintain 6 or even 8 cores. Till now only 4 were maintainable.
I think 20 dollars isn't so much so better get 8320. This price is worth!