My grandfather bought the Frick mill brandy new 58 years ago, we've cut a LOT of wood since. That being said, theres quite a few very incorrect debbie-downers in this thread. Milling lumber isnt the business it used to be, but depending on the area and type of person you are, its still a very good business to be in and one Ill likely be back in one day. My grandfather made a fortune selling to every Tom/****/Harry who wanted to build an addition themself locally, today it survives more bc local mills have grown scarce, high end custom work done by picky custom builders/true craftsmen, local contractors, and bc its in a very wooded location - contractors often trade logs that were removed for home building or otherwise free + cash for lumber. Bc of the industry shrinking the last few decades, equipment is also relatively cheap, big old planers are slow and need work but are nearly free, often youre competing against only the scrappers. Yes, rough cut lumber doesnt bring much, but a cheap old planer, a properly built solar kiln, and a few weeks (not months/years as others in this thread believe) will produce some dam fine lumber cheap. That being said, theres a ton of learning and experience necessary to do any of that....
As for the bandsaw mills, we know folks locally who have them and often refer customers to them for oddball size/shaped logs simply due to wood recovery, you waste less with a bandmill and small stuff isnt worth our time. Personally, Id never build one as old Woodmizers are dirt cheap bc many werent anything to brag about new. The low end Woodmizer for instance was only ~$1500 ten years ago, today I see theyre up to ~$4k but still making the same old design. I'd suggest finding someone who hasnt kept up with pricing and buy their old one for what they paid or less.
Just as a caution, cutting wood is one of the most labor intense and dangerous jobs you will ever come across as many here have said. My Grandfather often said that he paid $3 to workman's comp and insurance for every $1 he paid the 30-odd guys working for him years ago, today its run with family muscle alone bc its unaffordable otherwise. Even with a heavy duty frontend loader with forks for moving logs and a good ergonomic setup with the mill otherwise, hucking boards from the carriage into the planer, or even just manually stacking it for a few hours will wear your *** out like nothing else. Theres also a lot of danger in mills, trees have rocks/nails/other steel that they grew around and will become missiles when cut into, machinery breaks, and heavy logs do roll without provocation at times. I even remember seeing the big circular blade on the Frick get straightened and launched off its arbor once bc of a railroad spike we cut into....scarey ****.