Depending on where you live in Florida, expenses may be very different. What part of Florida are you in? In the south, hay is very expensive, like $12 to $16 a bale. If it is a good year in the south, you don't need to feed hay at all. If there is a drought, it gets very pricey.
Where I live in N. Central Fl, hay is $5 a bale for coastal and depending on whatever else you want/need, the price goes up. I pay my farrier $25 for a trim. Most horses in Florida don't need shoes, unless there is a health issue. I give my own shots, so that saves me several hundred dollars. My equine dentist's daughter is my daughter's pal, and she gives me a huge break, so teeth are $60 to $80 a year. I think a regular equine dentist charges about $100 in our area. Farm call fees are high here because everyone is so spread out. Farm call fees were cheaper when I lived in Melbourne, FL.
My horses don't need any special kind of feed, so my feed is between $10 and $14 a bag, depending on what I decide they need.
Board around here is about $200 a month for simple board, no amenities. I have two neighbors that have nice pastures and modest barns and charge that. No arena, no wash rack, no gorgeous unlimited trails, nothing extra. You won't need blankets unless you are showing.
If you live somewhere near me, NW of Gainesville, I know a man that sells used tack, brushes, saddle pads, halters, leadropes, buckets, you name it, used, for VERY cheap. You can bring your horse and try on any of his saddles to check the fit. Just PM me if you are close enough. (Florida is a VERY big state)