I have several retail boxes of the standard edition of Wildstar. $15 for the code via Paypal.
Here's what you get upgrading a F2P account with a retail box code:
1 month signature subscription service (details here)
12,000 Cosmic Reward Points (brings you up to Tier 3 part 1 rewards outlined here)
Unlock 10 more character slots (brings F2P total to 12)
Mystery Box containing 1 of 2 rare mounts or a rare costume set. These can be sold on the in-game auction house.
All the unlocks from the character slots and the cosmic tier rewards are permanent even after your subscription stops. Each additional code adds 12,000 cosmic rewards points and another mystery box. The character slots will stay at 12 max unless you buy additional slots from the in-game store.