How do savings bonds work?

Question

I found some that were given to my kids years ago. Is the value printed on the face the value at maturity or the value when purchased?

Answer 1

Assuming you are talking about Series EE the value printed doesn't matter. I think it's there for tradition. When I was a kid, the printed value on a Series E bond was the value at "first maturity" seven years after you bought the bond. Now rates vary and interest is paid by adding value to the bond once every six months. Here's where to look:
http://www.savingsbonds.gov/indiv/tools/sbrt0607.pdf

Answer 2

You should be receiving semi-annual or annual interest checks and the amount found on the front should be the amount payed to your child at maturity.