imo, your best bet is to go to a florist (a good one, not in a grocery store) and ask them if they can order amazon calla lilies (those are the big ones). If you have a picture of what you want for them to reference, that might be a good idea, too. Near Boston, they used to cost around $12-15 each, but were the freshest possible. At least at the florist I used, they'd get them on their next trip to the wholesale market and would call me as soon as they were back in the shop. They went about twice a week, so I usually didn't have to wait long if I wanted something specific. It was a lot better than just waiting until I found what I wanted. Admittedly, where I live now, I have no idea if they'd be able to get what I want.