1-800 Dial A Hoe... 
In my 54 years on this earth there are few products I have purchased that I have been as satisfied with as the Mantis tiller I bought.
I love it, and am very glad I bought it. I use it all the time (I bought all the fancy attachments and use them- they all work as advertised)
Garden ping.
Good question and I’ll be interested in the posts.
My Troy Built 4 Cycle blower/edger had a tiller/trimmer attachment which I bought. I tilled my entire yard with it. Sure a $3,000 would have been nice but this did the job if you’d stop every 20 minutes or so and clear the knotted roots of the blades. Just about all tillers need that. This attachment was under $120 at Lowes. Good luck.
FR has a weekly garden meet every Friday. You might want to ask your question there and join us. Can’t remember who has the ping list now.
I'm looking at an electric model because I'm a pretty fair hobby electrician. But I'm not confident that any of the electrical models on the market will withstand the rigors of a fairly heavy and slightly rocky clay soil which is prevalent in SW Pennsylvania. In addition, even trees far away from the garden area send out runners during the off-season which magically appear with every tilling.
I have about the same size garden as you (only 20'x 45'') but am also considering that hiring someone to till it might be worth eliminating the footprint of keeping a piece of equipment or (in case of the electrical model), having the rotating tilling parts give out before the motor.
That’s a toy in my opinion but it may be all you need in FL. If it’s comparable to what you rented and in your budget then have at it. Personally, I like cast iron gear boxes on tillers and tines that weigh almost as much as the entine weight of the unit you’re looking at.
1-800 Dial A Hoe...
Have a Sears 5hp 24in tiller bought about 4 years ago.
Have to guess at price, maybe around $250. Never tuned up and runs great. 100ft by 100ft garden tilled twice a year.
I take the outside tines off and use it for hoeing between the rows all summer.
In Florida our sand (some call it soil) doens’t need to be broken up. There are no rocks to deal with, and no clay that needs to be dealt with. Your chore isn’t actually what most would call “tilling the soil.” All you need to do is break up the weed and grass roots and you’re basically done. The Mantis will work fine. For heavier (real) dirt in a garden that size I like the Troy-Bilt Pony. But that much tiller would be far more than you’ll ever need.
Another 54 year old chiming in here: the only time I’ve ever used a tiller it was a rented Mantis (here in KS the rental yards still have them) and I was quite satisfied.
(To Mr. K re your tag-line: no. At least not in the last generation: the moment the Soviet Union fell, Pravda immediately turned into an honest news organization, even if it’s a bit of a sensationalistic tabloid.)
One can purchase a MF 135 or a 600-800 Series diesel Ford Tractor for less than $3000 and plow up a large field, bush hog, and have a means of transportation if the SHTF. With a storage of 250 gallons of diesel one can live a couple of years comfortably after the SHTF. The tillers are gasoline and if the SHTF gas is going to be real hard to come by.
I believe that mine is a Troy Built. It has a 5 hp motor with 12”dia tines with 24” witdth. The motor sit directly on top of the tines. It cranks on 1 pull and works just fine. It chewed up 3”diameter roots when I intially broke the ground in my garden. My garden is only 12 X 16, but my friend uses it on his garden which is about 40 x 50. It was bought from a pawn shop for $100 in like new condition. A comparable one at Lowes is about $325. This is the minimun size unit that I would recomend purchasing.
My sister is big into gardening, she has had a Mantis for years. She loves it.
She Says: “it is mad as hell at the weeds”.
Mantis makes a good product that works as advertised from what I have seen. I use a 6ft rototiller behind a tractor and am trying to get away from tilling on established garden space through composting, vermicomposting, and building tilth. We are trying to arrive at woodchip gardening heaven (see backtoeden film) for our primary garden space.
I also think you would be satisfied with a good deal on a tiller from craigslist or you might consider getting bids from a few lawncare services that might offer tilling if it’s an annual activity. You don’t have to store or maintain a tiller that way and it would probably take a long time before you would save money with your own rototiller. It’s easier on the back too!
For a small, sandy plot look no further than the Mantis. Make sure that whoever assembled it at the dealer got everything snugged down good and then go gardening.
No fancy attatchments, just spinning tiller blades and you can actually till, albeit shallowly, your garden.
I planted potatos for the first time last year (just one 12 or so foot row) for the fun of it, and the Mantis loosened soil off to the side that I easily shovelled on the growing plants to keep them buried.
I put a throw-away pool up last year (one of those - you blow up a ring and fill the pool up, the ring keeping the top rim stabalized and whatever (I don't know how to describe it .. ), and after the initial leveling of a 12ft spot, I found the Mantis perfect for tweaking the absolute levelness of that spot.
My only criticism (and may be a BIG factor) is the Mantis is used in a way that pulls you along, your lower back muscles taking almost all of that pressure.
I eat naproxen sodium like candy when I use it.
Neat little machine for relatively small jobs.
My garden in SW Pennsylvania is approx 50 X 50