My brother has an ultimate crappy PC.
I need to find a new 450W PSU as his old one recently stopped working cheap under 20$ or 1200 INR
I think you shold consider a zebronics one, 450 watt psu as your requirements its very cheap something like 10$ or 600 inr it should save you some money. still beware they make inferior quality products.
For that money you're likely to find it hard to find a decent PSU
I'd suggest look for items by Supermicro or Alblecom, they do low cost PSUs that are reliable - you might wanna trawl eBay, I recently got one from there