We LOVE the Purex 3-in-1 laundry sheets, too! We get the refill pack and put a group in a gallon size ziplock bag. They are convenient and do not use a lot of room.
As for the dishes, we get a small bottle of dish soap and (I think) one dishwasher load of soap. We generally buy both at the grocery, since soap is cheap. We do get the smallest we can find, though.