When I was in Texas, I used to buy Disk drives in bulk through auction from PC manufacturers Compaq and Dell that didn't meet their QC, test these drives and sell the good ones to retail shops, PC repair shops and individuals. I stopped once competition became tougher, bad to good ratio of disk drives increased, and disk drives became cheaper.

In Japan, several people asked me to teach them English. So I teach them English, some pay me in food and drinks. I also figured out that I was good in helping others prepare for standardized exams TOEFL/TOEIC/GMAT/GRE/USMLE so that became my primary side gig.