Just to express an opinion, I think it's difficult to generalize about when to get a PCB made. Seems like too many variables - the complexity of the circuit, where the board will be used, and any desire to simply experience the process are a few.
The same might be said concerning where you should get boards made. I used BatchPCB to make two different 2" x 2" boards for a little less than $33 US - shipped. I could be wrong, but I doubt that I could have gotten these for substantially less elsewhere.
Perhaps there is a difference between those of us who get boards made occasionally and those who do it on a regular basis.
(Personally, it was worth it all just to see my name on the silkscreen!)