I
think 1,830 sq. in. of storage space for $70 is expensive. Having said that, I understand that your situation may not be the same as me.
For me, I have adjustable shelving in three walls of my garage, and I do not need the bottom rolling cart to match up with the top box. I just aim for the cheapest sq in per dollar. I end up getting HyperTough 41" top box 9,619 sq in for $60 a few months ago (
thread here). Not saying you will be able to replicate this exact deal, but black Friday, Christmas and end of year is coming up, and I am pretty sure you can get better deal than that small middle box.
I also bought International 56" top box (16746 sq in) from Sears. A few of us got into this deal at end of last year iirc. I think it was a clearance sale but with Sears, you never know if they will have another similar sale.