we just moved into our first house and it has a shower with no tub. with three children and the oldest being 4 i need a tub to bath the children in. how difficult is it to put in a tub in the existing shower. it looks like previous owners took out the original tub and put in just the shower. the shower is all tile, and measures 58"x31", and the drain is located on the right side below the shower head instead of the center. is there a better type of tub to get than others without breaking the bank.