the 2nd account onwards is only $30.. but you have to email Clickbank support to tell them it is not your first a/c and they will discount it for you.
I'm not sure but every product signup would be charged $50. Just confirm the same with the CB support.
No you get discounted from the second product onwards. Just say 'This is second product and the nickname of my first product is xxxxx' in the comments text box while submitting your product for approval.