Have your religion set up a rank that has a monthly fee, and get yourself assigned to it. We did this in Sanguis Astroism, but I'm not sure how well it went over. Soon after we implemented the ranks, I went back to Aspirant status for a while. It was something that was often requested by the members, though.
Edit: I am fairly certain that Tom was against any kind of automated donation, or automated golf transfer into a religion from a lord. I think his opinion was that if your religion was worthwhile, the players would make it a point to do it themselves.
I think he has, but it might have been over imposed tithes.
The difference between the monthly fee and a tithe is fundamental. One forces the noble to actually travel to a temple and empty his own pockets to do a one-time transfer. The other just involves a lord setting a tithe rate, sharing the costs with everyone of his region in a way that adapts to production levels (low production for a week will result in a less painful tithe) without him having to remember every X days.
One requires more effort, the cost is direct and personal, and the process must regularly be repeated. The second is easy, the cost is shared and impersonal, and the process is automatic. In a world where the law of least effort rules, that really sets it. Plus, it's basic psychology: people would prefer the government give eco-friendly incentives than they further increase gas taxes, even if these incentives will come out of their pockets just the same. As an elder, I am confident I could convince a great number of people to impose thithes upon themselves. Paying their fees, though? It's so much work with such little probabily of success that it's not worth it. Especially if the fee has accumulated for a while...