Having owned an RV rental company, I would advise seeking out Mom and Pop's on Craigslist or companies that specialize in Class A rentals. They are usually cheaper, nicer units and easier folks to deal with. The majors (cruise America etc) will typically offer a stripped down Class C and usually they are pretty beat up.
Class A's are a bit pricey and range about $350 - $500/day.
Having rented before you may be aware but just in case, Most rentals will have insurance already via MBA. It should be included in the price. If they charge extra, ask if you can get your own rider on your personal policy. They may also ask if you want the MBA rider for about $12/day. I would decline. Standard MBA covers you on all the state limits that you would normally have if you owned it yourself. The rider simply adds $1 MM in liability (which you would never purchase on your own) and it's really not needed.
Most will have a damage deposit anywhere from $1 - 2k. This will be refunded provided there is no damage but - buyer be ware - they can also use this money for a cleaning fee. Make sure it's spotless when you bring it back and note any dirt, smears, smudges, nicks etc before you go out. I was a stickler for the clean thing, our units were like brand new when they went out and I expected it to be that way when it came back. Otherwise I charged the fee. Also ask if the exterior is required to be washed. I never required this as I didn't want folks using washing materials that might damage the finish. Tanks will need to be empty and LP full, Gas tank full. Also ask about mileage allowance and gen usage. Those things can add up. Sorry I ramble but a lot of rentals will nickel and dime you on incidentals that you may be shocked when the final bill comes upon return.
Here's a few to look at:
Tampa RVPrivate onesThe daybreak and the Suncruiser are home runs on their daily prices and fairly newer.
MidFLA