My high school does it every other year and I, and all of my siblings have gone. Our most recent high school band trip was 2016 with my youngest sister, it was her last trip. My own last high school band trip, junior year for me, was 2010-2011 I believe.
I'm not sure about any of the cost related items, but since it was a band and they wanted to like stay in theme, we all stayed at the All Star Music Resort every single time. Most of the time the stays were around 4-5 days, like a Friday-Tuesday/Wednesday or something similar. I remember them trying to get rooms close to each other and separate by gender. During my years there we were a band of probably around 120 kids, with at least 100 going on the trip. I'm not sure about later years, though. I do remember that there were some difficulties one year when the rooms weren't as close as they'd like, like one room was around the corner from everyone else and nowhere near a chaperone room. Also, they put the chaperones, or requested, to have them in the rooms like in between kids every so often, so at least there was someone around when needed. But we didn't use the chaperones for anything else. They collected our room keys, or magic bands when my siblings went, in the morning by like 7-8am and you could get them back by like 6pm? It depended on your chaperone and when they were going to be back at the resort by. In the case that you needed it to prove that you were staying at the resort for like EMH, then the chaperone was standing by the entrance until a certain time, you had their phone numbers otherwise, to give you your band to scan and then give it back. They gave paper tickets to everyone, regardless of magic bands or not.
I do think that each student probably paid around $2,500-$3,000 for the entire trip, including airfare, we flew Southwest out of Philadelhpia, and buses we needed and whatnot. I'm not entirely sure of the cost breakdown of it, but I do think that they got all of the students some sort of dining plan, or deal, since we got a voucher a day for a meal at a quick-service location and also got the refillable mugs. The school also, through like the band's trust fund and fundraisers, got like a $50 gift card for every student to use.