I promote the vast majority of my active affiliate programs with Tradedoubler, who can be slow to pay.
I
am looking at getting a 12 month 0% credit card to help ease any cashflow issues and may be even have a go with the Prepay billing funded from the CC on Adwords.
I would be interested to hear how others manage cashflow and fund campaigns
PS - If the credit cruch will allow them to give me a hefty credit limit!