I need ideas for a birthday gift for my wife that are inexpensive?

Her birthday is next week, and due to it being summer and kids in day camps, as well as having gone on vacation last month, i'm pretty well broke. Generally we have tended to do moderately extravagant gifts ($150+) but that won't work. The only idea i've had so far is to go out to dinner and shooting pool on her birthday, but we fairly frequently do that as a date night anyhow. Some suggestions?