These seem to be the only 4 pack available on Staples and they are sold at a good price. They seem sturdy. We are using them for file storage. We stick a "Label of Contents" on 2 sides which may be necessary if you're storing files like we are. They can be stacked and seem to hold a bit of weight when stacked 8 high but it's probably safer to stack 4 high. There's always an issue with lids cracking no matter the weight but if you reinforce with good heavy duty tape the second you see a crack the lids seems to hold up again.
I have several of these plastic file boxes & add a couple every other month. Mine are stacked on the floor in the basement. The paper contents stay dry & safe inside. The boxes easily stack due to the grooves molded into the lids with corresponding areas on the box bottoms. I use accordion style folders inside my boxes