I went to one in late winter at a hotel with food, etc. It was about $400 for 3 nights, including great food, room, and sewing area. This was a sew your own project retreat. It was put on by my LQS and a mother daughter Longarm team. It was a lot of fun. I will probably go again next year.
I am going on another one at the end of Sept with my guild. It is 3 days, 2 nights, cost starts at $190 plus whatever classes you want to take and hotel is separate.