Sales tax in Florida is around 6% to 7% but many counties have an additional hotel tax so if you're booking near Disney your $100 room is more like $113. Not sure about Alachua County, but I'd bet their tourism tax is similar. Then there's "resort fees". These are like airlines charging baggage fees. Everybody is starting to do it. It allegedly covers stuff like the pool, the gym, parking, maybe wifi or breakfast, etc. Now you $100 room looks more like $130.
That said, a $100 room is probably going to be a dump anyway.
Prices for everything are going up. Parking at a house near the stadium used to be $5 or $10, it's over $30 now.
I would check AirBnB and VRBO as well as hotels outside of Gainesville itself. I would also increase your hotel budget.
Remember though, it's a 7:00 kickoff. You'll be walking back to your car around 11:00 and traffic is going to suck ass because everybody will be leaving at the same time.
I feel bad because this post makes it sound miserable. It's not. It's fcuking wonderful. It's amazing. It's worth all the time and trouble and worth every penny. I hope you have an absolute blast. Pay for experiences. The memories you make will be worth it.
Alex.