They are right, you can buy a ex500 (500 ninja) and sell it for the same if not more than what you bought it for if you are picky and find a deal.
Take the course, it will introduce you to breaking, leaning etc. again, and make you feel more comfortable on the bike.
Wear your gear, which includes boots. I had a 15mph getoff where I was coming around the corner and a car pulled out and I grabbed too much front brake while leaning, my front tire washed out and I slid with the bike on my leg.. my boots were rashed like crazy becuase the bike was on it, and I had a raspberry on my knee.. the biggest thing damaged was my ego.. if I wasn’t wearing boots it would of been nasty. You have a lot of small bones in your foot, so foot injuries are hard to overcome.
I also had a getoff while speeding around in the twisties (I used to ride beyond my abilities) and was able to keep my bike up and brake but ended up going off the road and hitting the ditch, I fell on my shoulder, hands, etc.. and came out of that one too, even though I was sliding across gravel, with just some slightly ripped up jeans, a rashed helmet and the shoulder of my jacket was rashed (jacket had armor in it), that was it..
