1. Hell yes. Somebody gives me a computer and turns out it doesn't work. Perfect time to complain, even if it were free.
2. Even worse than complaining about something you have that someone else doesn't, you're complaining about getting guff for it? Nobody likes a whiner.

I do believe it's acceptable to complain about the fungus growing between the walls before I bought the house. Sides without complaining alot of rights you have now wouldn't exist. You can complain about free stuff to a degree, if it doesn't work then I say complaining is okay.

Your needs first before others, just don't be a dick and not justify your complaints.

Complaining is all fine and dandy, but don't go around annoying people. I know someone who complains all day about every little thing and most people just can't stand being around said person.

1.) Yeah, I can think of tons of reason to complain about something you got for free. Just because it's free doesn't mean it doesn't suck. For instance, during New Student Orientation our college house was given free sandwiches. These sandwiches made me throw up during the first day of classes. It would be unreasonable to say I couldn't complain just because the sandwiches were free. (Haha, yeah, I just realized that we're not talking about food, but it still applies to not edible objects. My sister won a DVD of this cool looking anime in a Quick Draw contest at an anime convention, and she was really excited about it. She opened it, and it ended up being some Japanese porn DVD: someone had just switched the insides of the box. Just because it was free doesn't mean she couldn't get upset over being set up for a good thing, and then being disappointed.)

2.) It's okay to complain about small things, so long as you're not bugging everyone around you. It also depends on the amount of time and the frequency of it you spend on complaining. I've got friends who will dote on and on about a certain small thing that upsets them, and while I might lend an ear at first, a few repeats of the complaint get very tired. It's all fine and dandy to complain about how that pencil sharpener mutilated your pencil, but when two days have passed and you're STILL talking about it, constantly, it becomes quite annoying.

Free stuff, to me, should be taken with a sense of gratitude toward the one giving it.

We are more gracious, the more money we make in our profession.

 

1.) Is it reasonable to complain about free stuff? (The quality and what not.) Not food or anything like that but free shit that fits into the category of entertainment.
The first example that comes to mind is free MMOs, which is honestly a torn subject for me.  While on one hand, I don't see why the free players (the cash shop users have more right to voice dissatisfaction in my opinion) would get so worked up over a service being provided for free, I do agree with them that there's a certain level of professional quality that should be upheld, considering the company SHOULD be catering to all players as potential cash shop users, and many MMO players invest a lot of their personal time into games they enjoy.  But when people complain about the most minuscule of things, yes it gets rather unreasonable.  Boohoo, the game glitched and you weren't able to pick up loot from a corpse.  That's no reason to raise hell on the forums as if you've suffered some great loss.  Now if it starts happening every time you play, and you've submitted a bug report and been ignored/told the problem was fixed, THEN there may be some justification to your complaint.

Another example is visiting a public recreation area such as a park, and seeing it in shambles.  Yes, the park is free, but I'm not going to shrug off the fact that some jackass decided to have a picnic and leave his trash behind, or that there is profane graffiti all over the playground equipment, or a drunk urinated on the park bench.  While I know I could just as easily go home and never visit that park again, if we remain completely passive about it just because it's free, it will eventually go to shit because of our apathy.

2.) Why do people say that you shouldn't complain about little shit? Because someone else has a worse situation than me I shouldn't feel angry or complain about it? Do you agree with that?
I think everyone has the right to complain at some point, so long as it's not overdone.  It vents frustration, which is more healthy than continuously bottling it.  Yes, there's always going to be someone who has it worse than you do, but that doesn't mean you should grin and bare every negative aspect of your life all the time because of it.  For example, you can damn well bet I'm going to complain if I had a horrible day.  Sure, there are people who have had far worse, and perhaps putting it in perspective may make my day seem better in comparison, but that doesn't suddenly mean I didn't nearly get in an accident on the interstate, have a fight with a close friend, receive news about a death in the family, and lose my wallet. 

It also depends on the way someone complains.  While I'd be fine with someone venting their frustrations about a dissatisfying experience, I'd be significantly less tolerant of someone who was point blank WHINING about something that's not that big of a deal, especially if they do it on a regular basis, or they're complaining about something they could have easily prevented from happening.