Covered litter boxes work well for nest boxes, too.
We priced litter boxes and they were expensive. The only way I'd use a covered litter box is if I got it cheap in a yard sale or thrift shop. But I agree, a new one is very nice. If you happen to have a smaller-size plastic dog or cat carrier, they work well too if you leave the door off. Again, one has to shop around to find a good deal. So far, our best deal $$$ was the HOMZ tote and because it is so compact for a bantam to lay her little eggies.