Three Speed MTB
The $35 Hub
This hub is offered by several companies at various price points. It is a essentially a Formula BX-2210 BMX Cassette Hub with 135mm spacing and an upgrade to cartridge bearings. It can also be found as a Novatec (Joy) D256SBT. Other companies branding it under their own name are Woodman, Planet-X (On-One), IRO, and Bontrager. Many others may exist, but the cheapest one I was able to find was the Nashbar NF-SSHR. Cost $34.95. That is CRAZY cheap.
The Nashbar hub includes a sprocket which some of the other companies neglect to include.
Internal parts
Converting to Quick Release
The hub comes set up with a bolt-on axle. Pretty lame by modern standards. It needs to be converted to quick release and do on a serious diet. The solid axle is a literal boat anchor.
Since Bontrager is now using this hub in both itterations, #250795 Bolt-on and #271412 Quick Release, we can source parts through the local Trek dealer.
The Bontrager hub retails for $79.99. It's a good price, but we can make that cheaper. Quick release axles, #SP-271397-TRE, can be ordered for $20. That puts our total hub cost at $54.95. Nice.
Gearing The Cassette
The cassette lockring is a standard 1.37x24T right hand thread lockring. Same as old school bottom brackets. I replaced the cheapo one with a nice old Suntour version that I had in stock.