With Keno it depends on how you bet.
You can generally pick up to 7 numbers....get all 7 win big prize .... get 1 number, win like 1 token when it cost you 7 tokens to play (just an example not an actual figure)
But you can pick say 2 or 3 numbers, get all of those numbers and win a nice prize without spending a lot of money, and even if you only get 1 number you generally get your money back
I guess it also will depend on where you are playing keno and what the rules are...