Also, I should add that with threads like this it's important to remember the audience when soliciting fashion advice. You're generally talking to a bunch of college students that have likely had relatively minimal "professional attire" exposure short of wearing an ill-fitting suit.
Perhaps most importantly, your suit should be well-fitted. It should cost no more than $80-100 to get a suit tailored to fit you correctly, pants and jacket included. As long as your suit is one of the "usual" colors I don't think it matters all that much, though I personally lean towards navy blue. I would agree with avoiding black. I'm also not a fan of pinstripes, but this is my own preference and not some hard fashion rule.
If you're concerned about your ability to get something that looks good, bring someone with you or ask to talk with someone at a store. Another option might be to go to a place like Men's Warehouse, get fitted, get some initial ideas for options and then go somewhere else to look at stuff. Buying a suit really isn't that complicated. If you go to Macy's, you can get a relatively decent suit for less than $300. Throw in a shirt or two (which you might be able to get on sale for ~$50 each), some socks (2-3 pairs for $30), and a pair of shoes (the sky is the limit but you can get a decent pair of shoes for $100, especially if on sale), and you're good to go. Yes, it's a lot of money, but it's also an investment - assuming you take good care of your suit, it'll last a while. I still have the suit that I bought for med school interviews and wear it occasionally, and with a shirt the whole get-up was ~$350.
As I was writing this, I was watching the Dreamhack stream and the commentators were up:
Don't be the guy from the second to left. His entire outfit looks like crap but his suit looks poorly fitted. The guy on the left and the guy that's second from the right both have well-fitted suits, though I would question the latter's choice in pocket square and tie. The guy on the very right looks like his suit is reasonably well-fitted, but his shirt looks like crap.
TL;DR: Decent suits are somewhat expensive but will last a while if you take good care of them. If you're uncomfortable with making these decisions on your own, take someone with you and get their opinion or go to a department store or suit store to get fitted and get some starting style opinions.