To access the market, click on the icon on the bottom of the screen. To navigate to the different market areas, tap on the tab on the top of the screen. Each tab is labeled with the type of items inside. For instance, you'll find all the various types of shops under the "Shops" tab.
Houses are buildings which provide a gold payout every few hours. They can be upgraded like shops for an increased payout amount.
Shops are buildings which must be restocked with Goods and provide payouts in varying lengths of time. They can be upgraded using Collectibles to increase the amount they pay out - but this also increases the number of goods they need to be stocked with.
There are various ways to obtain free gold or diamonds for your game, for example by watching promotional videos or connecting to Facebook.
It is possible to buy additional gold, diamonds, or goods for your game.