By now, it shouldn’t be a surprise that independent bookstores are having a hard time. There’s Amazon, the growing popularity of e-books, rising rents and the fact that while bookstores can have loyal followings, sales aren’t really increasing.

Those were the challenges that Borderlands Books in San Francisco’s Mission District was facing. The store specializes in sci-fi and mystery books, and its owners say it could have kept chugging along if not for yet another factor: a San Francisco ordinance raising the minimum wage, which is $11.05 an hour now and is scheduled to hit $15 an hour by 2018.

“By 2018, we’d be losing $25,000 per year,” said Alan Beatts, an owner of the store. And so, Beatts announced earlier this month that Borderlands would eventually close.

But at a public meeting to discuss the store's future, customers urged him to reconsider. As a result, Borderlands decided to try a paid sponsorship model to keep the store open. Owners said that if 300 people bought a $100 one-year sponsorship by the end of March, they'd be able to keep operating.