My suggestion... Go into the following places that sell suits, explain you know nothing and see what type of information you can glean from them.
1. Tip top
2. Hugo Boss
3. Harry Rosen
4. Calvin Klein
Keep tabs on the suits you like. IMO, Calvin Klein is a great combo of comfort, style and cost and a good entry level suit. But that's just my opinion.
They should explain to you things like how a suit should feel, the fitting/how it should look, "Sometimes, always, never ever.", whether you should unbutton a suit every time you sit down, Sportcoat/suit jacket/blazer differences etc. which is more than you will ever need to know about the suits. But, they might help you avoid silly mistakes like showing up in a tux.
After learning about suits, keep your thoughts open about taking it to a tailor for sleeve shortening, back seam modification, waist adjustment and pant hemming. This is huge as a good fitting suit looks better than a more expensive suit that doesn't fit as well. Average cost probably between $150-250, but you will have a great fitting suit that looks proper and not disheveled looking for a long time (assuming your body shape and size isn't going to change a lot).
Also, if you don't want to be laughed at, make sure you cut open your pockets before going to work on day 1.