Answers

According to the CollegeBoard, the average score for each section is around 500, which means the average for the test is about 1500. You can check out the CollegeBoard's average score report here:
Average Score Report

I heard it was around 1750

The maximum score is 2400 right? So the average score is probably around half, or 1200. I'm not sure at all if that's right or not its just a guess

The advrage score according to CollegeBoard.com is about a 1510. I mean, thats just the adverage, it all really depends on what school you or the person in question is looking at or field of study. If you're interested in Cornell or Yale and wanted to go into their Law programs, the adverage is more like a 2200 or somewhere around there. Whereas most state schools are much lower and make for this adverage of about 1510.

So then what is the lowest score?

i think that 600 is a pass..? or something like that..XD