Finding a gym is very difficult. Playing outdoors is the pits unless you like road rash, but it works if you must. I think your best bet is to inquire at a local school district or a private school. A gym teacher friend might have some pull (and keys). Some churches may have facilities to rent. It helps if you're already a member of the congregation or on speaking terms with Magic Johnson.
Rec and Parks are usually booked unless you can locate a friendly park director and play late at night. Prices will vary.
I still play a game that sorta resembles bball every week. Been doing it for the past 20 years. We have an ever-evolving group of 10-13 guys that kick in the quarterly fee that LAUSD charges. It's about $35/hr. in L.A. The skill level of our group isn't too wide; it's still fun and challenging for the guys who play. On some nights, the game points (usually 10 buckets) exceed the number of turnovers.
It's also an excellent workout to augment the time in front of the tube.
Pickup games are fine if you have the time. If you play like me, you'll end up waiting a long time after your team loses. If you bring 10 buddies to a typical p/u game, don't expect a welcome mat unless they're hurting for bodies.
And if you happen to be in the Pasadena area sometime, let me know if you want to play.
Good luck with the search,
Sherwood