If you are not shooting more than 100 yards, I would try Winchester and Remington rifled slugs. They are cheap and accurate. They leave a little leading in the barrel that you would need to clean after 20 shots or so.
In my Tracker II 20g, the Winchester rifled slugs are capable of bulls eye performance at 50 yards from the bench, no sand bags and no rest.
You do not have to break the bank to kill deer within 100 yards.