I have a vintage Singer 28k hand crank, which is a 3/4 size machine. Very cheap to run, can be used outside, as you provide the power! It will only straight stitch but you can still get lots of different feet, attachments and even a buttonhole attachment.
I wouldn’t pay more than £40 for one as there are still plenty about. If it’s just for occasional sewing a hand crank is great, but obviously you can only guide with one hand. Having said that when they were made that’s all they had and still managed making clothes.