Honestly, I'd probably take $100. I see now these originally went for like $150. A normal badge costs $80.
Well, the badges are your tickets to get into the convention's rooms. Like the panels, vendor halls, etc. Without a badge you can't do any of the convention stuff. You want to keep it on your person (usually they come with a lanyard). Obviously you still have to pay for your hotel, transportation, food, etc. This just gets you into the fun.
There are tiers where you get more stuff. A standard 4-Day Badge will get you into all the normal stuff for every day. A "Plus" Badge means yo get your 4-day ticket but it also has an exclusive poster and t-shirt that comes with it. So you have some special souvenirs built in!