Meaning if the rent on an apartment is $2,000/month = $24,000/year, the broker's fee on that would be $24,000 * 15% = $3,600. The cheaper apartment are usually owned by small landlords who use brokers to vet applicants. For those apartments, you're required to use brokers. There's no way to opt out by working with the landlord directly as the broker's fee is paid by the renter. The broker provides their services to the landlord for free.
I'm trying my absolute best to find a no fee apartment, but it pretty severely limits my options. For studio or 1 bedroom apartments under $2,500/month, there's currently 1,362 no-fee apartments [0] and 3,395 apartments at large (so, 2,033 for-fee apartments) [1].
[0]: https://streeteasy.com/for-rent/nyc/status:open%7Cprice:-250...
[1]: https://streeteasy.com/for-rent/nyc/status:open%7Cprice:-250...
[2]: https://www.brickunderground.com/blog/2015/12/in_case_you_mi...