lap top graphics are (except for a few very new ones) fixed as part of the computer motherboard. You can't replace them with a cheaper one (or with a more expensive one).

In fact *you* probably can't change them as you have to remove the broken components from the circuit board and solder replacement parts onto the mother board without damaging anything else on the computer. Unless you are a skilled electronics worker this is probably impossible.

You can pay a repair shop to fix the laptop - go for someone who offers board level repairs - or you can replace the motherboard of your laptop. But these are both expensive options and for an old cheap laptop you may find it cheaper to buy a new one and copy your data over.

In most laptops the graphics "card" is integrated onto the motherboard so cannot be replaced.

Laptop graphics are part of the motherboard... you're gonna have to fix the whole motherboard.

It may be cheaper to just buy a new laptop though.