I have read the rules covering the ratings many times but they are still a little blurry. Is there a number you can reach that will not allow you to play advance anymore? I see people playing in advance with 970+. If I had that rating I would try to make some $$$$$$$.
You can play advanced with any rating (even 1000+), as long as you have not given up your amateur status.
The two ways to give up your amateur status:
1) Register as a pro with the PDGA.
2) Accept cash (or prizes in lieu of cash) in a PDGA tournament. Accepting prizes in an amateur division is ok. Accepting cash for ace pots as an amateur is ok as well.