I’ve flown into MIA a couple times, it’s pretty easy to fly in and out with no delays (unlike Teterboro), I had to fly directly over the field of KFLL to avoid commercial traffic and then direct to MIA and land 8L both times. Signature is right there off the runway.
I was there this year maybe 4-5 nights, 10gal of fuel and parking was about $250 total. I’m fine with that. I was overcharged once so check your receipt, when I called they told me cheaper rates on the phone, so make a note of date time and who you spoke with. I ended up getting free parking the first time I went because that’s what they told me if I bought fuel but maybe it was a new staff, the $250 price was paying for parking, I think the first time I paid like $120 or something. The neighboring airports are not that much cheaper. I did call around and some were like $35-40/night parking. I guess if I found free parking or $10/night then I might opt for that one instead but I didn’t. And I didn’t want an hour+ Uber because sometimes you cannot find Uber when it’s too long / remote and I’m traveling with my dogs too.
If you want an expensive airport then fly to Sitka or Ketchikan in Alaska. $12/gal and even a $50 parking fee while you take up fuel. Easy $500-600 bill for a piston single.