I live in Los Angeles, I see homeless people regularly and give regularly. When I don’t have much money I don’t give much, when I have more I give more. I actually specifically got the ATM and make sure to carry $5 and $20 bills specifically for this. I am lucky enough that I can afford to give what I do but I regularly give people$20.
Definitely do it. It is a great feeling and helps them. Don’t let the fear of being scammed prevent you from helping people.