Cheap source of encoders

Hello!
I am starting my first DRO, and I am trying to minimize my expense.

I would like to know of sources for surplus or used encoders. I have
seen a few on ebay. Is there another source?
I tore apart an HP 500 inkjet printer and found the encoder and strip
was of 150 cpi, and that is not fine enough. Are there sources in
other products or different printers? Where else can I scrounge? I
am in Columbus, Ohio if anyone knows of parts sources here.

Thanks for all your help.

Mike