Yes I've bought lots of things on eBay.... including coilovers.
If your after cheap no name coilovers don't bother! As RS Phil says...
(Buy cheap buy twice!!)
Buy a well known brand that people have used.
Like if BC,Tein.... etc.
Spent 2k on my last set recently, best 2k I've spent since my AP's.
True words too,
If it means saving for a few wks more it's worth it