If all you want to host is a "slippy map" tile server for maps, but no search features, it's considerably less.

In my case, it's not hard for me to create an off-laptop VM as a resource... I would not want to attempt self hosting OSM on my own laptop. No matter how powerful it is.

If it's for any sort of for-profit company use (like the ISPs using openstreetmap for network monitoring maps I mentioned in the same thread), fairly powerful used 16-core, 1U and 2U rackmount servers with 128GB of RAM (dell r620, r720, etc) are available used for $430. Then add a couple of 1TB SATA3 SSDs.