Baby gate made from a pallet. Total cost $15-$20 depending on the hinges and handle that you pick. I did put a clear coat on it after I was done sanding it. I chose a handle that is for screen doors and so it can lock from the inside. The best part is that my 5 year old can work it, I don't have to get up to open it each time for him. Here is the link to my step by step tutorial. http://davidandallisonhardy.blogspot.com/2015/01/diy-baby-gate-from-pallet-materials.html
Storage for pool. looks Easy to build. believe the bottom would have more holes for water draining. Maybe staple some sort of screen inside the bottom also to keep small critters out and probably some casters or short legs to keep it off the ground.