Which is the best PPC to promote Email Submit?

Hello,
I have been in IM since last 2 years and earned well but still i am like a newbie though i've learned so much things in this period.
I am interested to know if is there any good PPC or advertising network where my campaigns can perform well?
basically i am more focusing on email or zip submit offers. i heard 7search gives good traffic but some members here in BHW are complaining about them.

will you guys please share your experiences? please !!
i will love to hear your experiences...

Thank you

Google adword is the best if you can get cheap CPC rate