Well, I figure if I at least buy helmet, gloves and jacket, I can test-ride used bikes and ride friend's bikes. And it makes my mom happy. (Actually she's not thrilled that I'm buying a bike at all--my dirt bike made her cringe and if I were still living at home she wouldn't let me get one at all!)
What about boots? Being female, I'd prefer something a little more stylish, but I know that off-road, boots are one of the most key parts of your equipment. I rode without boots for the first 2 years and bought a cheap pair when I bought my bike. I traded those in after a few months on a much more expensive pair and would NEVER ride without them again. Of course, you don't have to kickstart a street bike, and I won't be jumping it, or hitting rocks/trees/stumps/roots/other bikes (hopefully).
My off-road experience has given me a healthy fear of falling and a real appreciation for the right kind of equipment. I have over $1000 in my off-road gear!