(1) I have bought a number of suits in my life. In fact, I wear a suit everyday and have been doing so for a very long time. It is interesting bc a department store may not be the best place to get a suit. You need somewhere with a tailor on site so that the suit fits well. You do not have to get the most expensive suit in the world but, let me tell you, if it fits well and its well tailored then you are good to go. Now,don't get me wrong it truly makes a difference to have good materials so seriously keep an eye out for that, ie you never want a suit that will pick up lint, etc..... I would say shoot over to a Men's Warehouse** or another suit store where you can take your time trying things on and everything will be tailored to your size after you purchase it. For example, you try the suit on and then the SA will bring the tailor over who will then pinch and prin so you know how it will fit; then they take 2-3 days to tailor it and you pick it up.
Alternatively, you could run into Chanel or Armani and grab a decent suit but that would be a lot of money.
The best advice I can give you is to truly take your time and buy nothing until you feel good about it; so think about it in terms of buying a scent, try, try, try and do not ever be embarrassed if you walk out of the store with nothing bc this could take multiple visits to different stores.
(2) A decent suit will run you around $400-500.
**BTW if you know anything about buying a suit you will realize that Department Stores do not have tailors on site, its a fact. I work next to a Macy's and they do not have tailors, in fact, stores like this advise you to take your suit to a dry cleaners to have work done; weak!