Here is my problem with those who say how much they have ridden without a helmet...
The OP asked if it is a good idea to pick one up. Nobody here was pushing the idea on him. He considered it himself. In this scenario, I find it highly inconsiderate to not recommend the helmet just because you rode so many years without one.
I don't wear butt pads or any other type of armor, but if someone was considering picking some up, I would absolutely recommend it.
Why? Because how horrible would it be if they injured themselves in a way that a simple piece of equipment could have prevented? Especially if the person was considering it in the first place and was able to afford it.
It is indeed a personal choice, but you should always err on the side of caution when providing gear advice to new riders regardless of your personal choices.
Same goes for drug abuse. I used to do that shit. I always told my good friends to avoid that shit because addiction sucks. That's not being hypocritical, that's just warning people of the side effects.
To the OP: You can find damn good helmets for under $50.