So far I've managed to avoid participating in any weddings. Hopefully that will remain the case for some years to come. The only friend of mine who might be getting engaged any time soon is male with a big family
so no go there.
A lot of my friends have been in weddings, though, and a lot of them have been done "on the cheap" as many of us are young and certainly in no position to be blowing wads of cash. My good friend's older sister got married three years ago and all the bridesmaids bought their dresses at Ross or some similar closeout store for $10. They deliberately got together and went out looking for matching dresses they could all wear that would be cheap. Another wedding I went to the bridesmaids had to buy their own dresses or supply their own dress that went with the wedding's colors. It was great because all of the bridesmaids were different sizes and so there was no way they were all going to get matching dresses (way too expensive). So that turned out well.
As far as I'm concerned being in a wedding costs money, and if you're upfront and honest about the cost timewise and money-wise, there shouldn't be a problem. If people don't want to pay, they don't have to pay. Hopefully, though, they feel you're worth the cash.