@ashhtayy - I've been a bridesmaid a handful of times, including MOH for my sister's destination wedding, and I've always paid for everything! I actually have not heard anecdotal evidence of bridesmaids NOT paying for their dress, hair, etc., though I imagine it happens. But a destination wedding is different - and if you can afford to help out with the costs I think that is really nice, but not necessary.
While we aren't doing a "formal" bridal party, we are still doing some small things to recognize our would-be bridal party. I got the girls this simple bracelet with a turquoise band and gold starfish to wear at the resort that week (our resort logo is a starfish and we're using it on a lot of our stuff). My fiance is working on some t-shirts for both the guys and girls. I also asked the girls if any of them wanted to get their hair/makeup done - completely not necessary or expected - and most of them do! So I'll have breakfast with them on the wedding day and then we'll all be together in the spa just like a real bridal party.
My sister (would be MOH) will be my witness, will hold my flowers, etc. etc. And we'll do pictures with them and have them sit in the first 2 rows at the ceremony - so basically we're just not asking them to wear a specific outfit and it makes it easier for everyone