Thank you so much for playing and for the helpful feedback!
I like the idea of purchasing the alternate world mailbag as an upgrade option - great idea!
Originally I had designed the desk upgrades to be much harder to get (the first one was at 100 stamps and the final one at 1000), but I lowered it significantly for this game jam because I was concerned about player attention span. I also originally had 12-15 pieces of mail every day, but I lowered that to 4 - 6. I appreciate the thoughts that a more expensive desk upgrade could be a tweak instead of adding a stamp bonus to the repairs (or possibly additionally).