So my daughter has shown interest in piggy banks. so now we're making our 3 banks and emphasizing saving, spending and sharing. She still is learning the denominations but we think it's never to early to instill the 3s.
We explain sharing as being similar to what we do with our weekly tithing. I'm not sure if that's correct but it seems to work for her.
Oh and she asked how to say pee and poop in Spanish. Just in case you were wondering where the 4 year old is, she threw that in for good measure. :-)