While I designed a 3d printed knob, I know that it is going to look pretty crappy and take a long time to print, so I'm looking into other knob sources.

Somebody on Facebook mentioned this knob from Radio Shack (they still exist!) but it is $3.50 each, adding $150 to the cost of the project just for knobs!

https://www.radioshack.com/products/radioshack-hexagonal-control-knob-with-aluminum-insert

So the search for a cheaper knob continues:

~$2 each

http://www.mouser.com/ProductDetail/TE-Connectivity-Alcoswitch/PKES90B1-4/?qs=sGAEpiMZZMuHTYi1bHPYECayaa7y75Zb

~$0.70 each

http://www.mouser.com/ProductDetail/Eagle-Plastic-Devices/45KN018-GRX/?qs=sGAEpiMZZMuiwDVLTMm01aFL1PAiRZjKJa8LwXcTuU8=

Got the cost down to $30 for all the knobs, but that is still kinda a lot. Hmmm. Can I do better?

Oh hey, AliExpress has for $0.26 if I buy 1000 of them...
http://www.aliexpress.com/item/1000pc-lot-Replacing-Audio-Volume-Control-Potentiometer-Knobs-Black/32235472066.html?ws_ab_test=searchweb201556_10,searchweb201602_3_10017_10034_10021_507_10022_10020_10018_10019,searchweb201603_6&btsid=7c70a736-cedd-4bcb-8399-ea5e2d0c3008