Skin fold caliper measuring is fast, cheap and easy. You can go to any health club or gym and a trainer should do it, even if you're not a member. I would even guess a local Phy Ed teacher would kindly measure your bf% for you.
Just keep in mind it is an estimate. Consider the final bf%age a point in your range of actual bf%.
Underwater weighing for bf % is more accurate but who the heck wants to do that? Scales that have bf% capability are less accurate, but at least once you get a start point on those scales, you can go by that for subsequent measurements to keep yourself in check.