Ron: WGT has free weekly and monthly tournaments where you can win credits. One of these tournaments is the weekly CTTH . You do seem to play in the monthly sweepstakes CTTH events so you should try your hand at the weekly one.
The free stroke play weekly tournaments are also worth playing. The RTG Pro tier tournaments are a consideration depending on how many credits you feel like using and possibly losing. Just don't enter the open RTG tournaments as they are populated by most experienced high level players.
Still the best and least expensive way to build a surplus of credits is through free videos using a smart phone or an emulator and the WGT app.