How bad is it to use a PSU that comes with the case?

Hi, I'm really very close to completing my first ever Gaming PC/Everyday use PC. I've come to the hard budget point where I'd really like to save 20-30 dollars by not having to buy BOTH a PSU and a case. My question involves using a 45-50 dollar with a PSU to occasionally game on this rig, but not overclocking it or anything. If it is possible to overclock I might do it. I have heard a lot of nay-sayers going against the included PSU but is it really that bad? I am not going to be gaming intensely so I think it  would be OK but thoughts?

Well whats the power supply?

Need more info.

Real bad... I heard of a guy who's caught on fire. For the most part, they aren't even 80+ certified.

Generic PSUs are just bad news. They tend to fail around 75% load because the load they are rated for is for a 0'c temperature, not an operating temperature. So their real load is much lower. Not only do they burst in to flames when under load but they output unstable power which can damage your components.

Basically, just buy a decent PSU, they last for years and they stop your stuff from exploding.

It's generally the worst you can get. But if you don't stress them, they should work just fine. I would feel safe using them at half of their stated power.