Native speakers don't care too much about the grammar as long as they understand each other. However, when they are serious about the grammar, they are very good at it. There's several possibilities, this can be explained as there is, serveral possibilities. "There is" is singular, serveral possibilities is plural. So, it means one possibility from many of them. Precisely, the meaning may not be the same as "there are many possibilities." Note: ESL concentrate on grammar. But, in US, we train to analyse the sentence in accordance to the grammatical rules, it is called creative learning. Since many people use "there's" instead of "there are". Then, using "there's" is neither a slang nor an error. It is a creative word, it's meaning is different from "there are".

Hello Marja, When it comes to slang, colloquial or even lol cats speech you could expect to hear something like : "There is cheeseburgers? I can has one ?";)

Hello Marja Yes it is a commun mistake even by natives people ... There is + (singular noun) There are + (plurial noun)

You are right. The correct way to say it is: "There ARE several possibilities". And yes, "there's several..." is colloquial language. This is a very common error that is committed by many many native speakers. And I'm not sure, but I think the question should be, "....go out and about", not "...out and abroad".