There are two schools of thought on tool boxes, you have heard one of them in buy a cheap box it is the tools that make the money not the tool box.
Here is the other side. Cheap tool boxes are just that cheap. They do not hold up, the slides will fail, the drawers will start to sag, you will start to have a hard time opening and closing the drawers due to this and you will have a hard time securing the box due to the sagging drawers. The tool box itself will start to twist as you continue to put more tools into it adding weight it was never designed to handle.
I owned my last set of Snap On tool boxes from 1985 up till 2009, that is 24 years and the drawers still worked fine and none of the drawers sagged. These were all friction sliders as well with the exception of the bottom drawer which was ball bearings.
Back when I bought that box it was the biggest single bay tool box that Snap On made and I had both the bottom box and the top box. They were the KR650 and KR655 set. I was retiring in 2010 and decided to buy myself a retirement present for all my tools for my own use and bought a set of double bay Snap On boxes with a side box. They are the KRL722, KRL791 and the KRL711 boxes. 95% of my tools are Snap On. I have some Mac and some Matco some Cornwell as well as some other specialty tools from KD, OTC and a few others.
My advice is find a good quality tool box used that is from Snap On or Matco. I would stay away from Cornwell and Mac unless you can find a really great deal on a used Mac box but Snap On and Matco are better boxes in my opinion with Snap On first and Matco second. I would also stay away from the store bought boxes from Northern Tool, Harbor Freight and Sears. Todays Craftsman boxes are not the same Craftsman boxes from 25 years ago.
I started out with a 3 drawer used Craftsman bottom box in 1979 and quickly traded it in on a set of Snap On KR555 and KR557 boxes, then added the center box for that set and a side box. As I out grew that box I traded it for the KR650 KR655 set that I kept for 24 years.
My current Snap On double bay bottom, top and side box will last me the rest of my life to pass on to one of my grand children one day. I am just a do it yourselfer these days and my personal tool inventory comes out to $47,758 and change not counting my two floor jacks, motorcycle jack and my air compressor.
The MAC MB series & Macsimizer's are actually pretty good boxes, I had a MAC MB1800 for several years & it served me well. Don't care for Cornwell boxes though.