The supported cameras list on the wiki gives all the fully supported and mostly complete beta ports. If you are going to get a camera for CHDK, it should be one of these.
The for developers page generally also shows you which ones have incomplete/in development ports
http://chdk.wikia.com/wiki/For_DevelopersThe Ixus 330 (aka S330) is a pre-digic camera so will never be supported:
http://chdk.wikia.com/wiki/Unsupported_CamerasFor cameras on ebay, I suggest you make a search with old/lower end cameras from the supported list.
How flexible are the options within CHDK for timelapse ?
CHDK timelapses are done with lua or ubasic scripts, so if you have some programming ability, they have almost unlimited flexibility. Otherwise you are limited to using scripts that other people have written. There's a wide variety available on the forum and wiki.
In general, any CHDK camera will be as timelapse capable as any other, however if you are thinking about buying one, you might want to look around the forum and wiki a bit to see if there are any particular quirks mentioned. If you are planning to use existing timelapse scripts, some of those pages and threads may have comments about specific cameras.
