i have heard those vouchers are not available now. google isnt spreading those.
One time I wated a bunch of money in Adwords... turned them off.
Google called and asked why I stopped and I said that the ads didn't work well. THEN they said I should try again and I said I would not invest more money.... "maybe if I had another voucher"...
GOOGLE - over the phone - SERIOUSLY told me to create a new google account and apply a new voucher...
I thought that was against TOS, but whatever.