You might find a JA-XX number on the underside of the machine. It could tell you what Japanese manufacturer made the machine.
I'm cutting to the chase. It appears to be a clone of the Singer 15 that was manufactured in Japan after WW11. It's probably worth about $25.00. They are common. The ones that are colored in the bright colors like pink, teal and blue are worth more.
They are usually good sewing machines that could serve someone well, but are not all that valuable, money-wise.
If it interests you, there are some threads on quiltingboard that give you more information. Just search Singer 15 clone.
bkay