How to get film/polaroid-like photo effects?

How can I get polaroid photo effects like this on my photos?
I use a regular Nikon DSLR.
I don't have Photoshop, I usually just use pixlr or picmonkey for my photo editing needs, but I can't seem to find a good grungey-polaroid photo filter.

lol its cara delevingne's twitter picture ^

Here is a very simple way to do that.

http://poladroid.net/

When you use it, it replicates the funky colour, slight vignetting and produces an image in a 600 film frame. You supply the image and the program does the rest

I admire your good taste in photography. Film and Polaroid photos can look really compelling, unique and interesting in a way that modern, digital images can't. And therein lies the problem with your question.

While there are many types of software on the market that attempt to replicate the LOOK of film or Polaroid, none actually can. Why? Digital and film simply are not the same. Both have their strengths and weaknesses in different areas. But they just aren't the same and one can't fully replicate the other. More importantly, by using one to replicate the other, you can't fully appreciate the enjoyment of the process of using the medium of your look.

The absolute best thing to do if you truly appreciate and enjoy the look of film and Polaroid images is to buy a film or Polaroid camera and make REAL film and Polaroid images. That way, you don't have to fake it and wonder if it really looks authentic or not. That way you have a physical artifact that must be cared for and enjoyed; the negative or the Polaroid print. Digital doesn't give you something you can pass to your friends right after taking the photo at a party. Digital doesn't give you the random placement of organic grains. Digital's accidents are seldom as happy as films.

Digital is convenient. But digital isn't film and it can't be.

Yet because people want convenience and don't know of the fun of dealing with real film and Polaroid cameras, film and Polaroid are threatened. Polaroid actually doesn't even make film anymore. You can only substitute it with Fuji or Impossible Project instant film. Why? Because everyone is faking Polaroid instead of shooting the real thing.

To me, it's insulting to digital to keep using it just to imitate film. Surely digital photography is more than just imitating film.

You can be like everyone else who doesn't care and fake film with digital as various film products die off as a result. Or you can commit yourself to the look and history of the look you really want, and shoot film.

Use the free application that Fhotoace mentioned. That's all you need.