How do I unlock the Market? How does it work?

The Market becomes available at level 7.

It allows you to buy goods, materials and tools. There are 10 default boxes that are randomly filled with goods every 3 hours. The goods offered to be bought do not reflect your current needs and shortage of certain products. In order to sell goods, you can tap on them in your barn or silo, or sell them in orders on the PIers, for Paddlers or for jet ski orders.