Here's the cheapest 1650 on PCPP at $140 that also doesn't require external power and just so happens to come pre overclocked with a decent boost clock that's a bit higher than other options that are a bit more expensive.
And it's width should be small enough to fit inside the PC.
https://pcpartpicker.com/product/4q...verclocked-edition-video-card-vcg16504sfppb-o
But to be honest, I would highly suggest that if you're looking to do this as cheap as possible, that you frankenstein the parts out of this PC into a normal sized case, and get a normal power supply that can run something like a 1660 Ti (preferably about 400 to 450w)
Iam not good at these things so I didn't understand everything you said but I think that means I can't run this card and I can run 1650 but can you tell me what is the SFF version
And last thin do you mean 1650 super or normal 1650
SFF is what I spelled out earlier in the post.
It stands for Small Form Factor.
SFF is PC's that are smaller than normal one's, and usually they are smaller by way of also being thinner than a normal PC case.
And this creates a problem for adding in things like graphics cards, even ones that only require power from the PCIe and nothing else, as a lot of times, after market cards are wider than what the PC case can support.
Meaning that when you put the card in, the side panel won't close because the card bumps out too far.
I honestly would not waste the time, money, and energy on trying to slap a GPU into an old pre built SFF system from Dell just to try and make it play video games.
But you do what you want to if it's all you can attempt to afford.