BTW Susser and Casey are not dollar stores they are more c-stores like a 7-11 that offer gas/diesel as well. So you can't set up a comparison. Also their pricing is different among other business aspects.
DG is adding alcohol and tobacco which very much complicates their operations and removes any thoughts they may not be fully competing with c-stores which already make next to nothing on petroleum products. I think tobacco especially is a big mistake...they'll need to upgrade store operations expecially personell...theft will sky-rocket, help will be much more difficult to obtain. Sales will sky-rocket, but so will problems, not profits.