This one is definitely relative in my opinion.
Here in the Winston Salem, NC area, you can still find plenty of options <$70 per round range (with a fair number of $40-50 options). I would consider that to be a reasonable value for the courses in the area that I have played at least.
That said, we just moved here from Orlando, FL and that place has exploded. Good luck finding much of anything <$100 per round unless its twilight golf. The Disney courses made the jump a few years back and it seems like everyone else followed suit. Now, to be fair the courses are quite a few steps above what I have locally now, but over $100 to play 18 is a hard sell I think.