Purdue has a very wide variety of groups on campus. It is not uncommon to see people of other races, religions, or sexual orientations openly displaying their beliefs. I have never felt that anybody looked out of place. Chances are no matter where you are from or what you believe in, you can find a person with that in common at a university this size.
Purdue has no dress code. It is difficult to describe how a person would commonly dress here, but in generally people are pretty casual. For my own part, I wear jeans and a tshirt about every day. I have seen people who wear full suits to class even when they are in undergrad all the way to people who show up in pajamas ever day.
If you were to walk into a dining court here and see four tables of people, odds are those four tables would have people from all over the country and even all over the world at them. There is no real way to guess what who you'd see. In the end you'd see your fellow students and to most people here, that is all that really matters.
I have had classes where many people were from Indiana, but in most of my classes I have at least one international student and then people from America who are from all over the country. In one class this year there were 25 of us and no more than 3 of us were from the same state.
Financial backgrounds are not something most students share with one another prevalently at Purdue. I have met people who came on scholarships based on how little money they had growing up all the way to students who had hit it big by starting their own companies before college. There is no general statement to be made. At Purdue it really doesn't matter where you come from, it is all about where you can go.
Students at Purdue vary in how politcally active they are. Some know nothing of politics and avoid them while others seemingly take up a new cause every week. There are people from right, left, and center at Purdue. There are groups that debate politics and all kinds of clubs related to them, so it is not hard to find like-minded people.
Some students talk about the potential earnings of their career paths frequently, but others do not. I came to Purdue originally as a business student and that was one of the biggest deciding factors. Most students enroll in a program they will enjoy and argue that money really can't make a person happy.