I had 8 bridesmaids. 2 from NYC came to my shower and bachelorette party. Stepsister in FL, friend in PA, and friend in CA didn't make it to any pre-wedding festivities. The 3 local bridesmaids came to everything. I had 2 showers, husband's family paid for one entirely, my family paid for the other entirely. (1 in CT, 1 in MA). My bridesmaids paid for the dresses ($156), and 4 have already worn the dress again. They could wear any silver flat sandals (I'm not even 5 feet and 2 of my bridesmaids are in the 6 foot range). So, I'd guess their average cost to be in my wedding was about $500.... including travel, 2 nights hotel, and dress. We fed them well.
I was just in a wedding where I thought it was a little extreme to expect us to spend 2 nights in a hotel just under $300 a night.... I'll shut up on that after your $3,000 story!