Leeching is very expensive, and it really is not worth it at 1 dung to be honest. You are looking at 2-5M per floor, and so you want every floor to count.
Also, most good keyers don't sell floors below 30. Average prices seem to be roughly:
Ab2 - 2m
Occ - 3m
Warp - 4m
This varies alot though, I've seen floors alot cheaper (usually shitty keyers), and I've also seen Occ floors being 4-5m ea.