Hello Mindless.
Make sure that any long bobbin machine has the shuttle. It's surprising how many people don't know what the shuttle is and would cheerfully sell a machine without it.
Also ask whether it has bobbins. You need at least one to try it out. After that spare long bobbins for Singers are fairly easy to get hold of.
That old bracket around the first machine isn't for a hand crank. I'm a bit puzzled by it.