Needing to Finding the Value of Old Coins?

I got a whole bunch of old coins from when my grandpa ped away. Right now we are trying to save for x-mas but with the economy that way it is I'm sure my grandpa would want us to do what ever we had to do with the coins to help us out financially. So I'm from omaha and not sure on where to start as I do not want to have someone take advantage if I really do have coins worth some money