I'm late on this as well but normally if it is a good friend of mine I give $200-$250. But if it is Lance's friends he starts in the $300-$500 range and I think that is crazy!!
I use to give $100 and I was happy with that until Lance told me that he didn't like that, so I think it is based on your own beliefs!
Glenda I would just give as much as you can afford, I mean I don't think anyone would say you were cheap!! I'm sure they know you are saving up for a wedding as well!