I may have to stretch Category 3 and 4 a few years.

A local game store where I live has a Master System on sale for $150. I got my Master System on March 29, 2006 for $47.

Mind you, the $47 was from a different game store that usually had lower prices (That game store, Video Games Etc, closed on July 14, 2009).

A Master System would never have had a chance to sell for $150 in 2006. I seem to remember the store with the $150 Master System selling Master Systems in the $50-$70 range in 2006.

So the Master System has more than doubled in price in under 9 years.

Also, my boxed copy of Golden Axe Warrior - $15 on July 12, 2009 - is worth over $100 today. Mind you, it was worth about $60-70 in 2009, but Video Games Etc (which was two days from closure) had it for $15.