Most people start out mixing it with corn to get the deer used to eating it, but after that you should be feeding straight protein pellets.

Some folks do mix corn with soybeans and that is better than straight corn, but depending on where you are, soybeans might cost as much or more than protein pellets (corn costs nearly as much as protein pellets around here).

I use a 21% protein pellet that is made by a feed mill here in town and it is only $1 a bag more than corn.