You also need a category in your budget for miscellaneous expenses. Miscellaneous expenses can include a birthday gift, a cup of coffee on the way to work, postage stamps, a small household appliance to replace one that's broken, a haircut, and anything else that does not fall into another category on your list.
"I recommend the miscellaneous go into an envelope, and whatever you buy as miscellaneous, pay for it out of the envelope and put the change back in. When that envelope is empty, you say, 'I will not buy anything else this month no matter what. I'll do without it,'" said Larry Burkett.
If this category is not monitored, the amount of money you spend can grow quickly. Be creative in making do without certain things, and be wise about prioritizing items in this category; for instance, you could decide to get a haircut next month instead of right now. You could bring to work a thermos of coffee from home. You could pay your bills online to save on postage. For birthday gifts, you could make a homemade birthday card, bake some cookies, recycle a nearly new book or stuffed animal, or make a "coupon book" (coupons can include babysitting, a visit, a cup of tea together, a hug, a trip to the park, or a game of basketball, Frisbee, or cards). Saving money can actually be fun.
"Whoever can be trusted with very little can also be trusted with much" (Luke 16:10).