I just got my floral BEO yesterday. My bouquet is $300 and it's on the small side (calla lilies, mini calla lilies, mini gerbera daisies, orchids, another flower I can't think of the name of, and greenery).
We are having two pedestals to define our "altar" area (we are in Canada so there's no altar), and flower arrangements on top of that. The floral arrangements are in 8" vases and cost $200 each. Same floral as bouquet but no calla lilies. The vase rental is under $10 each.
Our centerpieces for cocktail tables and tallboys are a simple stem of orchids in a taller vase. The orchid stems are $7.50 each, with about $7 for vase rental.
Our brunch table (big round tables) centerpieces are 8"x8" for $150 each. Same floral and greenery as above, no calla lilies.
So it really just depends on how big you want to go and what flowers. A certain type of flower wasn't important to me, so I told the florist to give me what she recommends for orange and pink flowers. She showed me a bunch of flashcards for season flowers in those colors and I told her which ones I liked and which ones not so much. So I think it helped that I didn't want some of more popular wedding flowers that cost more (roses, hydrangeas, peonies, etc.).
We are keeping things pretty simple (no parent/grandparent flowers, we only have a best man each and no flower for them, centerpieces are not extravagant or over the top) and flowers are about $1,400 total. Hope this helps, even a bit!