Our circuits originally started as a counter to FFG not sending the Gencon winners to Worlds. Since they do that now, that issue is moot. My circuit this year still did that. We collected $75 from each qualifier, from the store, and used that to fund the finals pool. I paid cash to top 3, and gave prizes to all at the finals tourney. I ended up donating a lot personally, which was fine. One of the qualifiers I ran was at a geek bar, which allowed me to keep all of the door. I pushed that into the finals.
If you forgo the cash, you’ll have to come up with some other prize support. We had the top 3 at each qualifier be eligible for the final tourney, with an alternate available from each. The finals was a Swiss tourney with a T4 double elim cut. I am looking into some ANRPC prizes for 2017, which I can sell to TOs for ANRPC events.
I would suggest a down time in the FFG cycle to run a circuit. It will give stores an excuse to run an ANR event, and for players to attend one. I would say post-Regionals is a good time, which will prob. be June-September.