In the Shop you can buy different useful items: Officer EXP Cards, Reform Toolkits, E-Crystals, Cloaking Devices, Repair Units, PCB, Crates&Keys and much more. You need credits for deal – buy them for real money or get them in the game.
Second tab in the Shop – “Discount”. Here you can buy random goods with a discount. Amount of them based on level of your VIP. If VIP=0 then 1.