John,
I've seen em sell, if I can recall correctly, from "around" $180 to less than $400.
The physically bigger L880s come up a bit more, and are usually $180 to just under $500.
This spike in price happened with the spike in price of the L810s which went from around the $100 range to nearly breaking the $1000 range, and L570IIs, which wouldn't sell for $50, then were commanding a steady price of $150 to $200 for quite a while. The L630s are pretty uncommon- I've only tracked down I think 7 pair so far, mine being one of them. Prices for the 3 for sale went for $150, $212 and around $240 or $260.
Before the L780 and L880, there was the L630 and L730. The L630/L730 is similar to the L880- big difference is a different (larger) midrange driver.
The L630 and L730 are the same physical size, and the L880 and the L810 are the same size as the L630/L730.
The differences between the L630/L730 and the L880? Basically the move to a slightly larger midrange- a 2" compared to a 1.5".
The differences between the L630 and L730? The earlier L630 is an 8 ohm speaker, same size drivers though. The L730 is a 6 ohm version, cone material became the newly released "stiff-lite", and there was a bit of x-over tweaking due to new cone material I think, and most likely due to the drivers being 6 ohms.
I've got some L630s and L570 IIs if you'd like to hear them.
The L630s are one of my top choices among my collection. Not as tight in the bass as anL810, and at times can even be a bit boomy with improper placement, nonetheless it is a great speaker, and one I turn to constantly.