Lynx1611

I don't see how you can go wrong for $20.00 and the manual is free for download from Singer. (You will need it.)
Just make sure the bobbin holder is not broken. Use a magnifying glass and examine all the moving parts of the bobbin holder for cracks or breaks. These are expensive, $37.50 and up online. Pay special attention to the little bar formally known as the "rail guard". This piece is especially fragile and cracks even from normal use. I checked the one in my machine and sure enough it had a crack in the middle. I haven't replaced it is still in tack and appears to function. I found an inspection guide online but can't recall where I found it. I'd Goggle "Singer 600 series bobbin case"
and see what comes up.
I am in the process of resurrecting my mothers Touch & Sew 603E. I believe the 603E is a newer model but the mechanics are basically the same. This is an all metal gear machine and should be considered a heavy duty and reliable machine. The root of the "Touch and toss" reputation is the automatic bobbin winder. I found a lot of chatter about the automatic bobbin winding mechanism. They are apparently a pain to adjust correctly and very fussy. I haven't been able to check anything because the foot control for mine is damaged and needs to be replaced. I found one for $14.95 locally and plan to pick it up later today. It is an imported electronic unit and not the OEM part but should be an improvement over the circa 1950 style foot control originally supplied with the machine. (I have seen a lot of foot switch styles and controls but never anything like this one. It actually looks like a early 50's design, very expensive and somewhat frail. I'd recommend replacing it even if its functional.)