The best deal i ever did was buying 30 A1200 spare mainboards and 15 A600 Boards for lovely 50€.
Since then i can sleep very good as i know i will have spare parts for the next 10 years.
The worst deal i ever did was 1996. My A1200 had a severe hardware crash and was totally defect. I was so in depression that i sold all my Amiga stuff.
Just a week late i wished i had never done this.