Seriously guys, this is NOT the good deal that they make it out to be! I'll try to save you all some money by sharing my observations:
1. Bonuses DO NOT stack. Whatever tier you have reached, you will choose ONE of the items from that tier or the tiers below it.
2. Once you have redeemed ANY reward, your progress is reset and you are back at tier 0.
3. At the highest tier, should you choose the lucky box, you have a CHANCE to get the schoolgirl outfit of your choice. For all practical purposes, assume that you will be getting the Narak Relic x16 or Pet Hunger Hack x6. The odds be never in your favor.
In summary, if you reach tier 6, you can basically choose between a guaranteed ~1200 AP bonus in the form of 9 Narak Relics or a nearly guaranteed ~1600-2500 AP in the form of 6 pet hunger hacks or 16 Narak Relics. Therefore, gamble or don't gamble as it pleases you, or take advantage if you were planning on a purchase anyway, just don't be fooled into buying AP just for a shot at this promo.
Have you read the <a>Item Mall Guide</a> yet?