Here is the direct link to the source along with the links to the sales (click the 'dangerous waters' button):

http://www.cheapassgamer.com/topic/316950-amazon-pcdd-11-gta-trilogygtav-iv-749-gta-iv-complete-249-fallout-3-679-fall-out-3-goty-20-rayman-legends/page-276#entry11361094

Link to amazon:

http://www.amazon.com/Month-Subscription-Online-Instant-Access/dp/B00GDHD3LW/

Prices should chance on the 19th.

If this stays up he should be fine https://www.amazon.com/dp/B00GDHD3LW/ref=cm_sw_r_cp_apa_4zt1zbDD4AF89

Two things come to mind, I believe the issue you're having is the 2nd:

1) The address you're using must be a US one.

2) If you're trying to upgrade a trial account you have to purchase a starter pack and not simply gametime.