What laptop will play minecraft multiplayer lag free under $300 usd?

You could always turn down the render distance and it will stop the lag

For 300$ you would be better off buying a huge bag of lollypops instead of a gaming laptop.

There isn't a laptop for $300 that can do that, atleast a new laptop under 300$. Your best bet is to browse ebay or amazon or look for sellers in your town that are selling a laptop.