Advice on startups

Hi members

I am totally new to the industry so any and all advice will be highly appreciated.

I intend on investing in a printing machine in order to print my own marketing material but at the same time I intend on doing prints for other corporates.

I understand that there are 2 types of machines namely digital and offset printers and I am looking at an used offset machine.

I intend on printing on gloss paper and binding A4 and A5 magazines to start off with and then to start marketing the printer to other corporations.

My question is, what machines should I consider and where do I start looking for decent used machines.

Regards

Pieter