is it illegal to buy pair of fake beats?

Regardless of what others say, no, it is not illegal.

It is illegal to manufacture or sell them with fake trademarks in the US, yes, but buying them is not in any way against the law.

Even if it were illegal( which, trust me, it isn't ), you could claim that you didn't know they were fake; they can't prosecute you for being scammed.

Just don't expect the quality of the real deal.

You are going to buy beats from China? To what end? What is your intent? Oh well, no matter, yes, it is illegal, so you might as well simply download the true originals illegally for free from US bittorrent sites instead of paying Chinese vendors for already illegally stolen beats. I mean, if you are going to be illegal, be illegal in the US, not China.

It's illegal - trademark infringement, counterfeiting, etc. Just buy the real things, or another legitimate brand that you can afford.

I can't decide if you're a hot looking girl or a dude with no testicles.