Chemotherapy drugs are generally cytotoxic and can cause major side effects, including vomiting/nausea, fatigue, hair loss and pain. The use of targeted nanostructures to deliver drugs directly to tumours has the potential to reduce the side effects by decreasing the exposure of healthy cells and reducing the amount of drug needed. DNA can be used as a structural material to build drug-delivering nanorobots, but questions remain over the practicality of this approach. Here we show that it is potentially feasible for DNA nanostructure drug delivery to be more cost-effective than the drug-only approach. Our result suggests that the barriers to the development of DNA nanostructure-based drug delivery are likely to be primarily technical, regulatory and ethical rather than financial, as the potential exists for this to be a profitable therapeutic approach.