Trying to replace my 11t cog as its slipping and my LBS said “the days of purchasing single cogs for your gears have been gone for about 25 years now.” Needs some advice.

In a different thread I saw it recommended to replace your smallest cog rather than the whole cassette if its the only one showing wear. I like to reduce waste and spending so figured this was the best bet for my slipping 11t. I really liked this shop but was put off by this message as I see Performance Bikes [selling them](https://www.performancebike.com/shimano-xt-csm771-cassette-cogs-10-speed-for-1134t-or-11-36t-11t-y1yr11000/p1386695?v=311826) for $6. They said PB must be taking apart whole cassettes and selling separately but I don’t see how that would be profitable for them.

by samyalll