Gift a gas card to one of the groups below in whatever amount your budget allows. Every penny counts. Fortunately most gas stations today have gift cards that allow you to choose the amount. Be prepared to pay for them with cash as many will not take a debit or credit card for these type of gift cards.
If you do not have much to spare, but want to help you can always go coin hunting in your house and vehicles. We always have change that has fallen out of pockets in cars, chairs, sofas, and in the laundry. Scoop it up, grab the change jar and head to the bank to get a total. They may not love doing it, but they will typically not charge a fee like the kiosk in stores do. To save time you may want to call ahead to double check. After the bank the next stop is a chain gas station that offers gift cards.
Hand deliver, slide it under the door, or mail the card to whomever you please.
It can be anonymous if you prefer.
Consider adding a little note with some positive encouragement for an extra special gift.