If you want to start sewing, almost any machine will do. Frankly, I would start by asking family and friends if they have a working machine they don't want anymore. If you stick to vintage Singers (NOT touch and sews), there are lots of tutorials on YouTube on how to thread and operate the machines. If you decide you want a new one, don't buy too cheaply. You will have a lot of missteps in the beginning which may cause damage to a machine with all plastic parts.
I would make a list of basic features and types of stitches you need. If you are buying new, I would recommend an even feed system of some sort. I like the kind Brother has with the little pokey thing. Pfaff has an IDT system and Bernina has one as well. This will help a lot with piecing.
Good luck finding a machine. Join a Guild or at least go to one meeting. You'll get great advice.