Mars Box is a system of boxes that are sold by Mars fellows to users through the marketplace.
The cost of boxing depends on its level and type.
There are two levels of boxes - Epic and Legendary. Depending on the level of boxes - the user receives a unit of the corresponding level.
The types of boxes depend on the buildings you want to purchase. As it was said on the page with the description of the buildings, there are only 3 of them. So the boxes are divided into defensive, military (barracks), resource.
Epic boxes are purchased with Martian crystals.
Legendary boxes are purchased with Martian tokens.