I could be wrong, but I think most grocery stores, pharmacies, etc sell VISA gift cards.
With Uber, you can pay by credit or debit card, Venmo, PayPal, Google Pay (possibly Apple Pay -- I have an Android phone), and Uber gift card. I don't believe Uber accepts any other gift card.
If you go to the Uber webpage you will also see an option for paying cash, but cash rides are illegal in Florida (and most markets in the US).
For Lyft, go to lyft.com and look for payment options.
As a driver for both companies, I recommend that you have both apps on your phone. Prices do vary, and so do promotions, so it's a good idea to price check before you order a ride. Both apps are very easy to use and price-checking only takes a minute.
It also makes sense to have Uber on your phone if Lyft doesn't service your hometown.