Bloodborne and PS Plus

Recently bought my first console - PS4 Slim, and the new year going to buy the first game, Bloodborne, at a discount, if you will. And I want to know is it true that if I don't have PS Plus, I won't be able to use the multiplayer and the coop'om the BB? Is it possible to do without it? How much I miss, if I play without PS+?
And yet, I have this situation, that next year I go to College, and I'm not sure I will be able to buy or even play games. And so, should you buy PS+ for a year for free games, discounts and multiplayer?