You won't have much/any luck buying at those prices.
GP is worth around 30c/M right now.
13.5M * 30c/M = $4.05
$7.95 (cost for 30 days) -$4.05 = $3.90 Loss for the seller.
40M * 30c/M = $12.00
$22.50 (cost for 90 days) - $12.00 = $10.50 Loss for the seller.
On top of that, a lot of the very trusted upgrade resellers/flippres who have a lot more vouches/reputation than you buy upgrades for much more than those prices too.
You should look at some of the other threads around to get a better idea of what prices they go at.
~32M for 30 Days
~80M+ for 90 Days
Are the approximate market prices.