Hi Angela Rose,
I see on your Florida tour breakfast is included (it almost always is on JY hols) so I'd suggest around $50 a day, which should be fine for a light lunch and dinner. Budget for more if you have a hearty appetite or like to buy lots of souvenirs!
As Malcolm says, the sales tax is a pain as you don't know how much something will actually cost until it's rung up on the register but allow up to 10% on the advertised price.
Bring your visa debit card and/or credit cards with you and don't forget to tell your bank when you are going.
I'm sure the US govt shutdown will be sorted out over the next week or so and that it won't impact on your holiday at all.
Have a great time!
Bob
PS Don't forget to get your ESTA if you haven't asked JY to get it for you and get some TSA locks for your suitcase. The hotels might not have room safes and I put a second lock on my little rucksack (day bag) to keep things secure while I was at breakfast/dinner etc.