I know I'm only 4 days into it, but I was just doing the math on my little challenge, and I'm amazed. I have only bought one thing from the cafeteria so far this week, and that was a salad today because I misjudged on my meal size last night, didn't have enough for Dan and I both to have lunch, and gave him the leftovers. Seeing as I have a cafeteria with relatively healthy options, and his non-leftover choices are fast food establishments, I'd say that was the best option for all parties involved.
Anyway, on to the numbers so far. I've saved $3.50 a day on sodas by bringing my own. Not to mention, I'm drinking less soda and more water, which is never a bad thing. I figured the average price per meal in the cafeteria is about $5.99, assuming a mix of salad bar days and hot entree days. That's just shy of $18 as of today. I tend to get a breakfast burrito once a week, and also do a weekly trip to Starbucks (makes Mondays better). Eliminating those saved another $9.60. Assuming I keep up the good habits tomorrow, I'll have saved $51.14 by the end of the day. Holy crap!
It's amazing to keep track and watch what's staying in our pockets because of making a solid effort to eliminate the cafeteria from my life. I've started dropping the daily savings into our savings account so I can literally watch my efforts add up, and that only adds to the motivation.