One of the most frustrating things in New York is that everything is always much more expensive than (a) you think and (b) what the price tag says. One way to come up with a reliable budget is to use the following Price-vs.-What-You-Actually-End-Up-Paying-Ratios.

Digital camera: Add 30 percent. (Because the particular model you picked is out of stock, and the one that’s left is more expensive. Plus sales tax.)

Burger and beer: Add 60 percent. (Tax and tip for you and for that friend from Europe who left early and “didn’t know” that you have to pay tax and tip.)

Phone plans: Add 130 percent. (To cover F.C.C., U.S.F., T.R.S., A.B.C., C.I.A. and LOL.)