It really all depends on the area you live in and the parish where you are playing. In my area, the typical wedding fee for an organist ranges from about $200 to upwards of $500. One organist in our area charges about $800. He's a big name and runs a weekly organ showcase on the radio, as well as works at a very prestigious Anglican church. I don't think he does many weddings and probably doesn't have the time to, anyway.
Other instrumentalists charge between $200-$300. Harpists are usually a bit more. Singers range between $150-$300.
These fees could be lower if it is located in a working-class neighborhood.
The fees are usually thought up based on the amount of time you spend with the couple in choosing music, travel and mileage, music rehearsal time with other musicians, and sometimes the wedding rehearsal. Because most weddings are on a weekend, many musicians want to make it worth their time to be away from their families on days when everyone else is off and enjoying their company. When I do a wedding, I usually spend two or more hours with the couple either through emails, on the phone or in person helping them choose music with the liturgy, time every day the week of the wedding practicing the music, or learning a new piece of music, then time spent with other musicians if I'm hired to sing for a wedding that is not where I typically sing. I also usually show up at the church or other venue an hour or more before the time of the wedding to rehearse. I also start preparing for a wedding several hours before I have to leave to get to the place - warming up, practicing the music, getting mentally prepared, etc. Most musicians I know also do this. It often ends up being a 6-8 hour (sometimes a 10+ hr day if I'm traveling far) day for me, so all of that is taken into account when I set my rates.
Many bridal couples think that you show up maybe 15 minutes before the wedding and just play/sing without rehearsing, warming up, preparing, etc. so some don't understand why people would charge their rates. I will give breaks and discounts, though, especially if I really do get a feel that the couple is having a modest wedding with a small budget, but would like good music and musicians. I can't do it all the time because I would not be able to afford doing that, needing to pay taxes on my income and using that income to help support my family, etc. My usual fee is between $150 - $200, sometimes more if I'm traveling far or am required to spend an extra day of rehearsing with an instrumentalist on a day other than the day of the wedding. But I'll soon be doing a ceremony for just $80 because they only need me to sing the Psalm, gospel acclamation and Blessed Mother. I really didn't need to be spending any time with them choosing music or rehearsing with the organist and I won't have to prepare as many hours in advance. PLUS it's on a Friday, so I'm not giving up a weekend... huge PLUS for me.
Funeral fees are almost always lower, mainly because you are not usually meeting with the families and spending an hour or more choosing music for the liturgy. Not as much time is required to prepare as you often only have a couple days notice (sometimes only a day notice). You are also not doing much rehearsing and it's usually on a weekday rather than a weekend. Typical funeral fee around here is $125 and they are usually set by the parish or the funeral homes, actually. For instance, one parish I work at has the fees set at $200, both for the organist and the cantor. It's a more well-to-do area and parish. But at another parish where I work, the fee is set at $125. When I'm contacted on my website regarding funerals, I actually only charge $100, unless I'm traveling over 50 miles and then I'll charge mileage and gas.
One more thing, Protestant and most secular weddings usually have lower fees because you don't have to do as much music, it usually lasts between 15 - 30 minutes and it isn't as entailed as a Catholic wedding. The only time I charge more is when they have decided to have a 30-45 minute "recital" of prelude music with music they choose before the wedding, which is a lot more preparing than a Catholic wedding. :p