So glad you had a good time. Re the food...there are cheap alternatives. You can get snacks on the beach any day. Also, if you happen to have a kitchenette, you can get fish sold on the beach in the morning, or at the consortium that sells them. Lots of fruit stands around for your breakfast. The pineapple is to die for! Then, the smaller places are very good deals. Ambergris Delights is really cheap...great fried fish. I've heard Papi's is as good, but just never got there this year. Celi's Deli has the oddest, but quite good, tamales on the the weekend. Huge! I think Friday and Saturday, but check on that. Skip their key lime pie. Jambal Jerk has the best key lime pie, but they are a tad high end. Also, Celi's has many other economical goodies the rest of the week. Ruby's is great for breakfast. Then, there are always the stands near the pier (across from Jambal Jerk). I've been told the one closest to Front street really has great beef tacos. Never tried them, but people rave. Don't forget Mickey's. Their Mexican plate will handily feed two, and is a real bargan, and very good. The thing about SP is you can go from $40 to $400 a night for a hotel. You can go from $3.00 to $80.00 for a dinner. You just have to root around and see what fits you best.
Just remembered, let me add an addendum here, just tried Lagniappe last month. Oh, such good gumbo, and a very fair price. Right across from Fido's. Wish I was there now.