You might be looking at the Bussman 15300 series fuse/relay boxes. They come in different configurations: https://www.eaton.com/us/en-us/catalog/emobility/series-15300-rear-terminal-mini-fuse-relay.html
Pages 48-49 of the catalog: https://www.eaton.com/content/dam/eaton/products/emobility/CPCD_Transportation_Catalog.pdf

Normally 1530(3 or 5) - 2 is the 5 Micro relay and 10 fuse base. I believe it has one positive buss to all the fuses, and another buss for the relay grounds (when triggered on the high side.)
If using non-polarized relays, the relay bus could be connected to power through one of the fuses, and triggered on the low side.

I'm not sure why Amazon is $90? I actually ordered that one from Amazon on Aug 11, 2020 and it was $39.02 back then.
Waytek is $42.85 for the 15305 (metric screws) version -2-2-4

I noticed you can get them pre-wired with the fuses and relays on E-Bay, but they are expensive, $230: https://www.ebay.com/itm/132449489662