I found $640: now what?

[KKbluff]

You did the right thing.

About a year ago I dropped a evelope with $750 cash in it (I was on the way to my bank with the deposit envelope).

When I reached the bank I realized that it had fallen out of my pocket and started to worry ALOT (after all that was my entire months living expenses at the time).

AMAZINGLY about 4-5 hours later (around 8pm) the guy who found it called me.

Its people like you and him that I look up to with the highest respect.
It meant alot to me to find someone with that much integrity.

Best of luck.