Question Help with World of Tanks server!

I'm trying to make a server that the ranks are based on tanks from World of Tanks, and I want the first rank to be unchosen or unselected. Here's where problems appear, I can't find a plugin or plugin combinations for an inventory chest shop to act as "the tech tree". Also, if you are "unselected" how do I make it so you can choose between American heavies and German tank destroyers? Any plugin combination that will fix this? I also want to make it so you have to pay for the next tank/tier. I have tried PaidRanks and EZRanksLite. It would also be nice if different ranks get different buffs to simulate tanks firepower and movement, like strength for "artillery or tank destroyers" or "resistance for heavy tanks". I'm not good at making bukkit/spigot servers and I need help quite a lot but there is not much helpful videos. Thanks for the help! DDD