Your advice is correct.  I recently left Jaco to see some new turf, but for mongering Jaco is the place to be. My advice to the OP is to book a flight to San Jose and reserve a room at the Del Rey, just to experience that decaying and decadent dump.  Even better, stay at the Sleep Inn next door.  It's new and fresh.  The Del is like the bar in "From Dusk 'Til Dawn" called The Titty Twister, but without vampires.  There the girls only suck the money out of your wallet.  But it's a mind-blowing experience for anyone who's only mongered stateside.
Then rent a car ($100 a day) or take a shuttle bus ($40) to Jaco and if you're up for spending $130-$150 a night, stay at the Cocal.  It's newer and well maintained  and the scene at night around their pool bar is awe-inspiring.  Girls from CR, Nicaragua, Panama, Colombia and Dominican Republic, some truly outstanding.  Prices vary, but the best girls seem to be getting close to $150.  But unlike the states, you can negotiate.  And since the slow season is about to begin, you stand a better chance at cheap pussy.
Another great place to stay is one of the beachside hotels owned by the Del Mar; Canciones del Mar, South Beach or Girasol.
I've been living in a suite on the ocean at a price so low I won't even reveal it.  It's good to have friends in management.