This is such a complicated issue to address. Some priests are paid full-time salaries, and some are paid nothing or are even the chief support for the parish's finances. Some parishes are full of tithing members, and some have mostly non-contributing members.
I don't like mandatory anything when it comes to giving, but it is important to encourage people to give for the support of the church and its clergy. It is good for both the church and for the people giving.
If your priest is well compensated, I wouldn't worry too much about additional giving for "special services." If however he is barely paid or not at all, that could be more necessary than you realize. Bottom line is if you want clergy, take care of them. In the Old Testament they were provided for by receiving the best portions of the offerings of the people. Make sure they get the best portion now.
I say all this as a priest, so take it as self-interested if you're so inclined, but I will say that if I was ever given $1500 for serving a baptism, I'd probably pass out from the shock of it. I have been given anywhere from 0 to around $300, and would never let someone go unbaptized, unmarried, or unburied something so trivial as money.
Be generous with your priest as it is a gift you give to God. Priests, be generous with your people as a gift to God. If we all so that, we'll see how generous God is to us!
