I replaced my Plano system with RAACO a few years ago after looking at someone's system at ASLOK. I purchased bulk from Newark Electronics, making sure I got the quantity needed to get the deepest discount. It was still very expensive. I ended up with two extra trays filled with the modular inserts, but planned that for expansion. The biggest draw for me was the ability to mix/match inserts into a tray so I could just bring what I needed for a scenario if I was traveling for a game. Easily reduces the size of the travel kit without disturbing the overall sorting. When you return you can just place each insert back into its original tray. What used to be 2x Plano's (3701's I think) per nationality became one tray with the 16 inserts per nationality.
I think Texas ASL has a bunch of articles on storage systems that are useful in helping you determine what works for you. I know I read a few before I ordered and am glad I did, especially given the investment costs (for reference, at that time, it was a little over $500 for 16 trays each with 16 inserts including the shipping costs and tax)
Edit: I went back to see for sure, it was in 2019, and the total was $542, for 16 tray boxes and 256 inserts. They were shipped directly from England.