For some reason Spirit has a bad name but I've used them for over a decade and only one late departure from Ft Lauderdale to San Jose was an issue, otherwise I've had great flights each trip.
I'm in the $9 club and for chicken feed you can take as many as 5 full size pieces of luggage much cheaper than shipping stuff here, upgrade to luxurious huge front first class style seats for like $30, free one large piece of luggage and a carry on, choose your seat, things like that.
Their prices for that time frame range mostly in the $71 to $111 per flight, same deal, taxes and fees included, some occasional $120's and $140's, but most in that range. The last 2 weeks of November spike up.
South Floridians : No more excuses!!! Pick one and get yer ass down here!
Morazan and HDR are still cheap, someone who knows can update me but I'm hearing about $70 a night.
When I lived in Ft. Lauderdale when super cheap flights, even cheaper than this came up, me and my crew would shoot down for a 3 or 4 day weekend, stay at HDR for $65 a night and sometimes fly home Monday morning and be at work the same day, our suitcases in our trunks and a wicked gleam in our eyes at the young sexy secretaries and clerical workers...I'm thinking "Hey honey, I just slammed the hell out of a hot thing that looks just like you three times this weekend and STILL had time for 4 more....
" 
For super frugal guys, how about $125 a week at Vista Linda for a fully furnished one bedroom about $1500 to $2000 colones away, taxi, even cheaper uber, outside of 5 to 6 pm traffic... or even less than 500 colones bus which stops right in front of the place to downtown.
Super cheap? Ignore the $70, $80 even cien requests from potentially disappointing freelancers and go to Monica's or 360 or Relax and get 1/2 hour sessions for around $13 to 15k colones, one hour for 20k colones, a 5k colon and 10k colon tip respectively gets you pretty much everything, safe, away from your things in your hotel room, and almost always get the full hour.
Ok, figure $300 for flight, taxi, car storage at airport.
Vista Linda and taxi, uber, $150
One hour sessions at above mentioned mp's and possible occasional day girl low price from HDR or SL, $60 per session.
There's incidentals and you'll end up paying for additional things, condoms, viagra, tips, expensive meals eating out, whatever, but a cheap monger can get away with under a g note for a 4 day excursion