We went through Jetblue at Westchester Airport on our last trip, last July. I will not do it again if I could avoid it. Actually, it was the second worst air travel experience I've had in 30 years.
The airport itself is fairly small, which can be advantageous, but the terminal and luggage handling infrastructure are too small for the volume they're trying to handle. Security check was a backed-up nightmare, with luggage lying everywhere and none of it being supervised.
As far as the parking goes, yes, it is that expensive. And be warned that the number of parking spaces is very limited, especially during the work week. (This is a business oriented airport, so a lot of flyers leave their cars over night or for two to three days.) There are also NO nearby off property parking lots. So you may arrive at the airport with your car and NOT BE ABLE TO PARK ANYWHERE. There are warnings about this on the airport website. I was lucky in that I was able to find a spot on a Saturday AM, but I REALLY had to look hard to find one. Again, I saw absolutely no security patrols in the parking garage.
As I said, this is a small airport, and they basically roll up the runways and shut off the lights at 9:00 PM. This caused a serious problem for us, as our return flight was delayed leaving Orlando and we didn't reach Westchester until nearly 1 AM. Unfortunately, our luggage went to San Juan, Puerto Rico along with most other passengers' as well. There was absolutely NO ONE IN THE AIRPORT TO HELP US. We had to leave the airport and call the Jetblue office about five times in the morning to find our luggage. When we left the airport, I literally had to WAKE UP the parking lot attendant, who got extremely rude, to get my car out of the garage.
Needless to say I'm not real happy about Westchester. If you really want to try it, I would strongly recommend that you have someone drive you there and drop you off. Also make sure that your return flight is early in the day, so in the event it's delayed, you won't be arriving after 9 PM.
Another alternative is Stewart airport in Poughkeepsie, which is also a small airport but much more efficiently run. It's actually a closed Airforce Base, so it's not quite as "pretty" as Westchester. They have tons of cheap parking right near the terminal (I think it as about $50 for seven days our last trip). Staff is very friendly and helpful.
Either way I hope you enjoy your trip.