One way ticket to Chile
 

I already booked my ticket and noticed the note on the bottom saying that I will not be allowed into the country without an ongoing ticket.
I don't plan my trips this far in advance so I don't have an ongoing ticket yet.

What is the likelihood that I will be allowed in? I've read people saying that they got in with no problem with a credit card and playing dumb.

Anyone??

The risk is that you'll never get on the plane in the first place. The person checking you in for your flight to Chile will see the requirement and probably won’t let you board until you produce a ticket out of Chile.

Okay that's what it was worried about. Is a bus ticket okay? Or does it have to be a plane ticket?

No, a bus ticket will not do. The first hurdle is the check-in, as Jeff says. Playing dumb does not usually work well in Chile.

One solution is to buy a fully refundable outbound ticket.