I agree that Freerolls are extremely time consuming, but the idea of winning a few bucks and turning it into a large bankroll is so worth it, at least to me. I may just get lucky in freerolls, but there are a few strategies I've incorporated that work for the most part:
1. In the early stages of a freeroll, you want to play only your suited broadways and pocket pairs (I don't mind playing small pocket pairs in ANY position really, but ideally late position is best). LET THE FIELD THIN OUT. People say that freerolls deter them because of the huge field. I don't mind this because really, you're not up against 5,000 people in a 5,000 person freeroll. You're up against 2,500. Check out the tournament lobby as you play, people are shoving right away, raising way too much right away, cold calling right away. Sure, some of these people get lucky, but most lose. That's good for you because you will soon find yourself in a decent field of players and you can get down to playing poker.
2. DO NOT tangle with big stacks. After you've increased your chip stack (either from stealing some blinds or just doubling up against donks with your good hands), you're going to want to apply pressure. But applying pressure does NOT mean re-raising a big stack with Ace Queen off. Ace Queen is better than most people's ranges in freerolls, sure. But a big stack has you covered, and there's no point in committing a large portion of your chips to a pot, especially pre-flop, when your tournament life is on the line. If it's checked to you and you've got AQ, feel free to put in a standard raise against players with smaller stacks. But going up against big stacks with non-premium holdings is more often than not just bad news.
3. Be patient. A freeroll can take hours upon hours, all just for a few bucks. For most people, it simply isn't worth it. I can't really make an argument for the ROI you get from playing in a freeroll, for as they say, time is money. Since you're staring at a computer for at least a couple of hours, you probably would be making more money trying to find change on the street. But if you were going to play poker anyway, and you have absolutely nothing to lose monetarily, why not? If you rush your play, you're going to play sub-optimally. Wait for other people's mistakes (believe me they will be making plenty of them) and then seize the opportunity to make them pay for it.
4. Don't risk your life for a few more chips!!! When it's the late stages of the tourney and you've spent hours on the computer, stealing blinds, bluffing nits, doubling up, etc., the last thing you want to do is call a huge bet from a big stack. Let's say it's 10 people outside of the bubble. Someone's got you three to one in chips. He puts you all-in, you look at your cards and see Ace King suited. What do you do? If you can't lay this down at this point, you shouldn't play poker. In almost any other scenario I would probably call, but risking your entire evening's worth of hard work is simply not worth it here. It doesn't matter if he has 27 off. FOLD. You will get a chance to play back at him once you've guaranteed yourself a few bucks. (The only exception of course is if you're on the verge of being blinded out, in which case you really have no choice but to call.)
There's not really much else to it besides that. I certainly am not a poker guru, but you don't have to be when it comes to playing these free tournaments. Anyone can play, and that certainly means people that have no clue how to play at all. Play smart, have fun, and win a little bit of money for your hobby for free.