The "thank you' gift doesn't have to be anything big, like a large screen TV. It can anything like a gift card, a candle in their favorite scent, candy bag, or even a personalized Christmas (or Holiday, if they don't celebrate Christmas) card telling them how much you appreciate them.
To avoid hurting the feelings of other friends who won't be getting an extra gift from you this year, send them a personalized Christmas/Holiday card sharing your feelings and that you are glad to be their friend. Also, you can give the extra gift privately or send it to their house.
Want to thank your mailman or package delivery person? Since they can't accept monetary gifts, candy, gift cards ($20 or less), and food. Like I said, they can't accept cash or even gift cards from a bank or even a Visa gift card. The gift card must be for a retailer (like Walmart or Target). The gift card must be $20 or less. They also can't accept anything that can be exchanged for cash, clothing, event tickets, meal tickets, checks, alcohol, tobacco, or stocks. The best way to thank your delivery person and avoid them from getting fired is a note of saying "thank you"!
Remember- even a simple "thank you" goes a long way!