You know how Andre 3000 said "shake it like a Polaroid picture?" Yeah, you're not supposed to shake all types of Polaroid film. Bet you didn't know there were multiple types, huh. The on you're most likely familiar with is the old square looking film that resembles the Fujifilm Instax. You're not supposed to shake those. If you do, you could end up ruining the photo. The film you can shake are the peel-apart pack films. The reason you shake them is to dry them; not speed up development.
It's funny that Polaroid doesn't even make film anymore and Fujifilm has pretty much taken it's place. They've even created new cameras/film which are extremely popular - the Instax. Although Fuji has made an extremely accessible product, I find myself ignoring it and sticking with the Polaroid. Ironically, the film I use in my Polaroid cameras are made by Fujifilm. Go figure. You can find Instax film literally everywhere including the grocery store. Peel-apart pack film, not so much.
Fuji announced earlier this year that they have discontinued the pack film all together. First it was the FP3000-B (black and white) back in 2013 and now, FP100-C (color). Previously, you were able to buy a pack of film with 10 exposures for around $7. Once they announced the film has been discontinued, prices skyrocketed to around $20 a pack. If you're lucky, you can find them on sale for $15.
As far as cameras go, there are many different models and types. You can get them fairly cheap for around $10-$50. The two I use are a Polaroid Land Model 250 and a Polaroid Big Shot. The Big Shot is really fun. It was made famous by Andy Warhol and it's main purpose was for portraits. The flashes for bot the Big Shot and Model 250 are wild. They're one-time use bulbs. You need to replace the bulb after every flash. Not mention, these flashes are BLINDING.
If you haven't had a chance to shoot this film, I highly recommend that you try it at least once. The anticipation of waiting a couple minutes (depending on the temperature) and peeling apart the film to view the image is really a thrill every time. Anyways, I know I'm rambling, but I just love this film so much. Try it out for yourself if you can. Here are some of the photos I've taken in the past month or so.