Most US airports operate several distinct parking products. The economy lot (sometimes called "remote" or "park & ride") is the cheapest, sits farthest from the terminal, and runs a continuous shuttle. It is built for travelers leaving their car for several days.
Long-term parking sits closer to the terminal with a shorter shuttle or covered walkway. It is a few dollars more per day than economy and is the sweet spot for many 3-7 day trips. Daily / short-term garages are attached to the terminal, priced by the hour, and add up fast - they are meant for pickups, drop-offs, and meet-and-greets, not multi-day parking.
Valet trades convenience for cost: you hand the keys over at the curb. Off-airport lots - independent operators like The Parking Spot, Park N Fly, WallyPark, SmartPark, and SP+ - sit on private land near the airport and shuttle you in. Because they compete for your booking online, they almost always offer the deepest discounts when prepaid.
All five categories adjust pricing for vehicle size (oversized SUVs and trucks usually pay 25-50% more) and demand windows (peak holidays and weekends can carry surcharges). Booking ahead is the single biggest lever you have to lower the bill.