If you want to use film and sell stuff, then stick to black-and-white. Forget scanning anything - it has no benefits of any sort for you in differentiating yourself from a million other photographers. Print yourself, if you want something digitised then shoot the print.

A Pentacon Six will give you gorgeous 120 negatives. However, if you buy any sort of ancient scrapped camera then you will get unreliable results. P6's are available refurbished and with a guarantee, but not for free.

It seems the budget in time is effectively zero, but how about large pinhole photos shot direct to paper-negs, for example 40x50cm or larger, maybe retouched with pencil on tracing paper behind the neg image etc.? Lots of unusual and unique results for you. That would make your work different and interesting, especially where local purchasers could recognise the 'where' but not the 'how', plus you could make your own gear cheaply with foamboard and blackout cloth.