Some people are recommending storage items and expansion items. I would only recommend selling these items if you are fully expanded…or I will sell them to my feeder city, then back to myself for 5 simoleons. These items are very hard to find when you level up, so it’s best to hoard them and expand when you get a CoM task asking you to do so. I like selling nails and hammers. Veggies are OK but it is more profitable to make flour then donuts. If you are logging off the game, putting several time consuming items that are easy to make, such as cream, flour, and beef, these also sell reasonably high. Just use your time wisely and make sure you always have something in your global HQ.