At level 7 you will unlock the ability to put items from your barn or silo up for sale in your roadside shop.
When you tap on your roadside shop, the display will open. Tap on an empty spot to create a new sale. You can select whether you want to sell goods from your barn or silo. Set the price and choose whether or not you would like to advertise the items in the Daily Dirt newspaper. Tap on "Put on Sale" when you are done.
If you do advertise in the Daily Dirt newspaper, your products and their prices will appear in other players’ mailboxes each day. If you do not advertise your products, they will only be available to Facebook and/or Game Center friends and your farm followers.
Once a player has bought your advertised items in your shop, you will notice the picture of the customer where the item was. Tap on the picture to collect your profits.
If you want to delete products previously offered on sale, tap on the slot you want to delete and select the trash icon. This will remove the product at the cost of 1 diamond and will create a space in your shop again.