I was an English teacher, and the copy machine at school was always breaking so I would make copies at home.
I had 125 kids a day. I can't count how many times I was running out to Staples getting more ink cartridges -- and it was all coming out of my pocket.
I looked online and there are companies out there [that recycle cartridges], but it wasn't a flooded market. So [my husband and I] invested about $1,000 and found some inexpensive guy from Europe to make a website for us.
We developed a relationship with a company that takes cartridges that have already been used, and recycles them, so they ship them out to our customers.
Our cartridges range from $10 to $30 -- if you were in the store you'd be paying $25 to $50 -- and toner [from our website, CastleInk.com] for the big copy machines can be hundreds of dollars cheaper.
I'm making quadruple what I made teaching. At one point, we were getting so many sales a day we couldn't believe how much money we were making.
People were like, 'where are you getting this money to redo your whole backyard?' It's definitely nice to have, especially for a cushion for the kids. I'm putting a lot into savings for them.
Graduates from these colleges earn the highest salaries in the country, according to data from PayScale.com.