well, almost unlimited
but i got your attention.
what you need to do is
1.) open a regular adwords account (using credit card #1)
2.) open an adwords professional account (using credit card #2)
3.) assign the regular adwords account to be managed by the professional account
4.) assign the $40 coupon from the adwords professional account to the regular account
5.) after 90 days, pass the adwords professional test and double the amount and number of coupons available
rinse and repeat, as long as you got different credit cards available

what you need to do is
1.) open a regular adwords account (using credit card #1)
2.) open an adwords professional account (using credit card #2)
3.) assign the regular adwords account to be managed by the professional account
4.) assign the $40 coupon from the adwords professional account to the regular account
5.) after 90 days, pass the adwords professional test and double the amount and number of coupons available
rinse and repeat, as long as you got different credit cards available
