It’s difficult to find any reliable overview of how much has totally been spent on either side, but as far as I can gather from searching, it appears that even including all the donations for Ukraine, Russia has put about double the amount of money into the war than Ukraine.

Russia recently mentioned options for a ceasefire and basically claiming victory of the “special military operation” with current frontline borders. This is likely just an attempt to win time to restock, meaning that they’re running low.

So while the donations are quite large amounts, it has actually been surprisingly cheap for western countries to let Russia deplete it’s war materials this way.