I recently brought a laptop and it said i can get a FREE £75 Google Adwords voucher, i just found the form you need to fillout and filled it out correctly, however if you never brought anything from dell you can still get £40 free! Google AdWords | Dell United Kingdom I think this is for the UK Only.
I dont trust them, I had a £50 adwords voucher and they charged me £5 for no good reason when I cancelled and the £50 was nowhere near used up.
It says at the bottom of the Google page that if you pay using Credit Card there is a £5 activation fee, If using credit in the account its a £10 fee.
