> You can be sure that delivery fees will more than cover whatever the cost of gas, the cost of the driver, and the time it takes employees to shop for you so you aren't likely saving money, but the extra you pay may still be worth the convenience.

In theory, batching deliveries should delivery economies of scale on vehicle and labour costs.

Judging from other comments, the costs of gas and vehicle maintenance get pushed onto the drivers so probably aren't added to the cost of orders in fees.