Worrying about the cost of shells? Really? Is it going to break you to pay a couple of extra bucks a box? That is like buying a $1,000 rifle and putting a $100 scope on it because you didn't want to spend the money on a good scope.
I love it when that happens . Cost of shells dont bother me from what ive seen 410 is higher than 28. Plus 28 are easy to find around hear.