Nikon d40 error press shutter?

I bought a 50 dollar used nikon d40 from craigslist cuz i wanted to take a next step in photography it said on ad it had the "error press shutter release button again" message that the guy was selling for 130 but i got it for 50 then i looked up the problem and found the solution that there's a poorly made gear on the bottom of the camera if you just take off the bottom part that there's a red gear that has alot of play on it and it gets stuck someimes when you take a picture that causes that error but my dad wiggled it and we saw how to fix it on the web it worked but it kept getting stuck so we decided to take it gear but we took it to a local camera repair shop and they said its the automatic diaphragm but we don't think thats it and they want 124 to fix it i think the error is still gonna be there after they "fix it" do you think we should just get it back before the error comes back again after i pay 124 for no fix? And just fix it ourselves or try another place

So let me understand. You knew the camera had a major malfunction prior to buying it but you bought it anyway? What were you thinking?

Well you're stuck with it now. You bought it knowing the problem was there so you're not going to get your $50 back.

Get it fixed either by Nikon or a Nikon authorized shop. After that's done you'll have paid almost what the camera is worth.