I bought my 1975 Cessna 150 M in 1987 for $7000. Since then, while maintianing it to a high standard, and flying 2600 hours on it, it's probably appreciated to be worth three to four times what I paid for it. What a super investment, I wish I'd bought a few at that time!
I fly a Commander 114 occasionally, nice plane - I'm glad I'm not paying the bills though!