Complex sentence: With money, (or any commodity used as a medium of exchange) you can sell your fruit when it is ripe and take the money; then use the money to buy wheat when the wheat harvest comes in.
Split into simpler sentences: With money, (broadly speaking, any commodity used as a medium of exchange) you can sell your fruit when it is ripe and take the money. You can then use the money to buy wheat when the wheat harvest comes in.