I understand now. Like I say, don't charge too little because you'll be stuck there. Don't charge too much because they don't have it. Finding the price that both of you can live with can be a challenge. I guess the only advice I can give you is that typically event photoraphers charge in the $100/hr range. This is because there's a lot of other work involved other than the actual shooting (as you know!).

This rate may be higher than they can afford, but it might be a starting point. Rather than discounting the rate, you could throw in extra prints (maybe one for each person) which won't cost you much. Let us know how it turns out.