The Shop is a single-level building requiring Base level 6. Shopping exchanges the currency shown on an offer for the listed item or reward container.
Different shops use different currencies
Top Force has separate Alliance, Valor and VIP shops as well as other purchase sources. The currency associated with an offer matters; an item being available in one shop does not make it purchasable with another shop's currency.
Alliance Contribution is earned by helping allies and contributing to alliance technology. It can then be spent in the Alliance Shop. The Alliance Center opens alliance membership and those shared systems.
Items and reward containers
An item purchase and opening a chest are separate actions. A selection chest lets you choose among its listed options, while a random-reward chest follows its own reward rules. The name and description of the item determine which you receive.
The Shop's construction is a one-time building project. Its presence does not change the costs of Base upgrades, research or equipment work; those systems still consume their required resources and materials.