$30 - $70. They're not particularly high quality firearms.
25
25-50 USD
You don't you throw it away, I once owned this gun as a youngster, I was shoot at by gang bangers when I reached for this POS it jammed, I sold it and went with a 44mag bulldog
200-1200 usd
Take a round and press in the button on the slide and lift up but keep pressure on. The button slowly release the pressure and pull the slide forward
That is not a question.
We can't tell how far apart it has been disassembled. You will need to ask a gunsmith for help. It will not be the first time he has been asked to put a gun back together,
50-165
100-1000 USD or so
need to replace gun stock
Take it to a gunsmith