Maybe a new pair of pants.
Or a new shirt (they last longer on most people.)
I love hats, personally.
Also renting a really stupid movie and making fun of it with friends and a glass of wine (low carb dry red, of course.)
A low carb cookbook to keep you on track.
Fantastic coffee or teas make me very happy, not that expensive, and offer the enjoyment of a treat with low carbs.