Best PPC/CPM For Signups ?

Can you tell me some good sites to use for PPC/CPM that have good conversions for signups ?
I’m running some email submit campaigns with adwords at the moment and they are performing great, im looking to expand to make some more money but i need to know some good PPC/CPM programs out there please.
Does anyone have any recommendations?

See original post by Jack_Tomlinson