One of the things I really liked about the year I smoked cigarettes was being generous with people who wanted to bum one. Just a little bit of human kindness I could afford to share with people I wouldn't have talked to otherwise.

Give them Nintendo DSs and flash carts.

That's perfectly good. Dimebags can be sold and joints can make flying a sign go by easier. I'll generally kick down some smokes or a joint cause that's what I have on me instead of cash most of the time. There's one dude that I meet by the grocery store who doesn't do any of that and usually just asks if I can grab a few groceries for him. Even if they aren't gonna use whatever you give themselves, a lot of stuff can be exchanged. Like a dime bag is useless if they don't have papers and a lighter (lighters are also a good thing to kick down if you think to keep extras) buuuut as said above it can be sold or traded and I can say as someone who has been, has a lot of friends who have been or currently are and doesn't of my activism stuff based around, so the homeless aren't a nebulous blob to me, you get good at turning anything of some value that you don't need into things you do need.