Has no one answered this question yet? Honest zero fee pools survive off of donations. It's as simple as that.
I wasn't aware there was a scrypt coin that could be merge mined. I suppose I should look into that.
My pool is at 0% fee, but I'm not losing any money on it, since I pay for that server & have had it for years, anyway. The processing power & bandwidth the p2pool & dogecoind require is negligible.