Have you heard of "no spend" days? The concept is simple, to have days where you don't spend any money, and there are two ways that you can implement it. You can either plan to have no spend days (like every Tuesday, or whatever works for you), or you can let them happen naturally and then celebrate.
In the first variation, you pick a day and just decide not to spend any money. I envision this as being good for very organized people who can plan their lives, but if you are that organized, then maybe you're still spending the same amount but doing it the day before or the day after your no spend day. Anyone who has tried that, I'd love to hear what you think.
The second variation seems like it would work better for me. If I realized that I've got a day without any scheduled expenses (grocery shopping, needing gas, dentist's co-pays), then I can make it a goal to keep the rest of the day spend free as well. I have noticed that these days seems to present themselves pretty regularly. They are usually days where I don't leave my house! Maybe I should set a goal for myself to have a certain number of no spend days each month.
Another similar idea is to have months where you don't buy anything that isn't a need (again, food, gas, tuition.) By deferring wants to the next month, you often discover that you don't really want that this so much, or you forget about it, or you can't get it anymore.
If you are looking for creative ways to help yourself spend less money, a no spend day challenge might work for you. Let me know if you try it, and how it goes.