A propane retailer makes a profit by purchasing propane in bulk from wholesale suppliers at a lower price and then selling it to consumers at a higher price. Their profit margin comes from the difference between the purchase price and the retail price. Additionally, they may charge fees for services such as delivery, tank installation, maintenance, and rentals, which also contribute to their overall profitability. Effective cost management, strategic pricing, and maintaining a steady customer base are key to maximizing profits.