Remember the good old days when your friend's birthday rolled around and all you had to do was buy him a beer and a shot of tequila? Yeah, well, you're older now. You have a job and a kitchen table and an unlimited metro card: all of the things that say, "Hey, I can afford to spend more than $10 on you at a bar called PJ O'Flaherty's."
You don't have to go too crazy, though. Those are the perks of the semi-adulthood that you're currently stumbling through. Pick up a bottle of your friend's favorite alcohol (the nice kind, that doesn't come in a plastic bottle). Present it to him alongside this Shot Glass Card ($4.99, Fifty Five Hi's).
A card that literally turns into a shot glass, he can start the birthday festivities immediately. Like at the bus station or in the car. Cheers, buddy.