Need Help- Budget Wardrobe for Summer Analyst Internship!!!

Brief Intro: Junior in Undergrad starting my Summer Analyst internship in June. It is for a front office role at a BB.

Dilemma: Need to buy clothes for internship but 1. Don't know anything about business/wall street fashion 2. On a very limited budget (I'm in pure shock when I see people talking about $500 suits being cheap).

---------I really just want to buy some affordable clothes that look sharp!!!-----------------------

The Dress Code at the bank: shirt and pants enough for everyday work. When meeting clients (which is probably going to be rare let's be realistic)- full suit.

>Suit: If I were to buy one suit- do I go for navy? I don't care at all about name brands, I care a lot more about a modern, slim, aesthetic fit. What stores would I go for? My friend has recommended some stores such as Express and Zara for having cheap suits that look good (100-200 bucks for a suit).

>Shirts and Pants: How many would I need? Would 2 white, 2 blue shirts, and 4 pants be enough? Where should I go to find cheap shirts and pants that look modern and fit well?

>Shoes: I have a pair of black dress shoes with laces from Aldo. They were cheap and look great. Would it be ok for me to find something similar in brown- to pair with a brown belt?

Sorry for the lengthy post, and thanks so much for any input! This site has some really kind people.