The Tesla Shop sells normal and premium equipment. It uses a lottery system to dispense both permanent and temporary items. All players share a pool of 200 items in which there is one permanent version, several temporary versions, and mostly random items. When a player uses the Tesla, he/she removes one item from this pool. If that players removes the permanent item, the pool is reset to 200. The amount of items remaining in a pool is visible in the tesla shop menu(X/200). If you are calculating your chances of pulling the permanent out of the pool, simply divide 1 by the remainder of the pool. If there are 100 remaining, your chances are 1%, 50, 2%, etc.
The items in this table are slightly improved to the items purchased in the shop. Each item requires 7 purified ores.
The premium shop requires purified crystals, which you obtain through either achievements or by dissassembling "blue" items. Alternatively they are also for sale in the shop.
When using the premium equipment Tesla, each use will create an affect on your next use. These effects range from increasing the fever meter to boosting your chances at the desired item.
The fever meter in the shop fills as you use the Tesla, at 1000/1000 you are guaranteed a permanent item. However the meter fills up by 1 per use, unless effected by a previous use.