Cheapest probably is Dotster.com. Google: Dotster coupon - the second result is better than the first, as I remember. Anyway if you can find a 15% off coupon then two years of .LA are about $55.
What do I think? A sleeping giant that may never wake. The domain is really the country code of Laos, so there is a local population behind it, not some Pacific island with a population of 23 people and 4 dogs. And sometimes people try to promote it as Louisania and Latin America. But it is Los Angeles where this extension could boom. LA is one of the world's biggest and wealthiest cities. Some clever promotion, donate a few names to the LA libraries and whatever, the town could embrace the domain as it's own.
Probably never happen. I see no sign of the promoters doing anything beyond cashing the checks.
Oh, and those same promoters (they are one of the really big domain movers and shakers, I forget which one at the moment) decided that their predecessors made an error by selling one letter .LA domains so they simply sent the owners of those domains a letter saying that their domains would not be eligible for renewal. No refund or compensation, just the shaft. A black eye for .LA and the entire domain industry.
I own several very nice .LA domains, and sometimes I dream that the city will embrace the name. Really the only Country Code domain that has more branding potential is .TV. But for now it sleeps.