My budget is around 35-40 dollars.
Hello,
A computer is similar to a human "Cyborg." Or a human with augments.
It basically consists of a brain, a heart, and a neuro-skeletal system. This makes up a computer.
What is the most important part of a human being?
The heart.
The power supply is the heart. It is what delivers the electricity that every other part of the system needs to operate on. Just like the human heart delivers blood to all parts of the body.
Therefore, the PSU is the MOST important part of your system!
Everyone overlooks this. People are always looking at cases (you don't need a case to use a computer if you're careful), monitors and the vitrol-filled CPU wars (AMD vs Intel) and the flavor of the month motherboard and graphics cards. But a PSU is only given a passing glance--"buy just slightly more watts than you need", etc.
However the PSU should be your MOST important part that you research for your system! The PSU has to deliver steady, high quality voltage to the motherboard so the VRM's can feed the CPU and components what they need. A low quality PSU can not only make your video games crash and shut off, but it can even start a fire!! That's right..a bad PSU has a bigger chance of burning itself out AND killing your CPU and motherboard than anything else! And under worst case conditions, can cause a fire.
You do NOT want a gutless wonder powering your expensive and valuable computer system!
A high quality PSU has protection components in it that will not only detect faults in the motherboard, like surges and short circuits, and not power on if something is completely out of spec, but if a high quality PSU fails badly, it has a MUCH higher chance of the protection mechanism tripping and shutting it off, without sending 12v to your expensive CPU and destroying it. So it pays to do your research and buy a high quality model. High quality doesn't mean tons of watts. If you are only pulling 500 watts, you do not need a Corsair AXi AX1600i (probably the best power supply on the market), which is a 1600 watt unit. A high tier 650-700W unit will work just fine (just don't buy a 500 or 550W unit--you're cutting it WAY too close and efficiency drops off HARD that close). But please--expand your budget (may be hard in quarantine times) and maybe do without for awhile, until you get enough saved. Do NOT skimp on the PSU. Low end CPU's and video cards can be upgraded. Generally speaking, you want to get a decent motherboard and high quality PSU, then decide on RAM, CPU and video card support for it.