Buying Delta SkyMiles directly is rarely the "cheap" option. On average, Delta sells miles for , while those same miles are usually only worth about 1.2 cents when you redeem them.

However, there are specific strategies to acquire them at a lower cost or maximize their value so they effectively "cost" you less. Strategic Ways to Get "Cheap" SkyMiles 5 best ways to redeem Delta SkyMiles for value - CNN