It's hard to believe, but there was a time when $12 was a big deal to cofounder of World Wrestling Entertainment Linda McMahon, who has an estimated net worth of over $1 billion with husband Vincent.

Long before World Wrestling Entertainment was called that, when her and her husband Vince were just building the wrestling promotion business, the pair had to carefully consider whether to rent a typewriter for $12 a month or to invest and buy one outright.

"With any small business, you are really running on your cash, it's about cash flow and you have to manage that cash flow, especially if you're only operating on the cash that you're generating" — which is how the McMahon's business was operating at the time. They would invest money made from promoting wrestling in one regional television market to expand into a new market, explains Linda McMahon, head of the Small Business Administration, during a recent SBA Facebook Live.

"So there were a lot of little things, like the typewriter," says McMahon. (They ended up leasing the typewriter at first until they could eventually afford to buy a better model.)

At the time, McMahon could never have imagined the scope their business would eventually reach. But an experience during those lean days taught her an important business lesson: Prepare for opportunity and success, even before you have it.