One can collect many different things and one can collect cash. Pick a favorite denomination and collect those dollar bills, like the $50 bill. At first it may not be much but after a while but after a while, it will add up. Coin collecting can be great too and can be a wonderful hobby. Here is how it works: pick a denomination, then collect and keep that denomination in a safe place. Also, keep a record or ledger with the cash. For example, one can collect the $50 bill. One important note is to not spend the cash that one collects, but this will be addressed at the latter end. Keep it until retirement or pass it on as bequeathment. It is merely joy to collect and should not be considered spending money. On the other hand, if one wants to collect cash for a certain item one desires to purchase, the favorite denomination of choice ($50) can be saved up for that goal. An example of this might be a new computer or tickets to a show, or even a nice vacation. Buy something with it or save it for another time. It can also make a good gift, a monetary gift for birthdays or holidays. Asking others for a monetary gift can be just as exciting yet tentative as to receive. Yet another thing one can do is to save every denomination ($1, $5, $10, $20, $100) for different goals.
$1 for new music
$5 for a book
$10 for a steak and lobster dinner
$20 for a new watch
$100 for a new house
Once the cash has been saved up and used, it can be saved up again. Consider giving in the same way.