I have an old macbook with an old OS. The stupid apps store wont let me update to a newer OS and offers no explanation. It seems I cant download any new apps because they only run on the newest OS, I don't have enough space, and my video card is obsolete. Is there a way I can pirate an old version of Imovie or final cut pro or any other free video editing software that I can get to run with OS 10.6.8.
yeup, you can.
Its still going to be slow as shit, but it will work.
How do I get it?
I would but I'm very poor. I actually wanna edit videos so I can win a local film festival. I would consider running linux on my macbook if it didnt break the thing.
Ya Lion and newer is only compatible with the newer Macs because Apple's build quality is awesome (for the most part) and if they made the new OS's fully backwards compatible they'd lose a lot of money because people would rarely have to upgrade. You can still get PPC Macs in perfect running condition, that's pretty hard to say about other PC's, but you won't be running the newest software.
Basically the best luck you'll have is probably running Linux. Then you're not limited by your software, only what your hardware can handle.
I ran linux on my older macbook air (2011) and it worked really well. I don't know how old yours is, but I say give it a go. You can always re-install OSX if you need to but it sounds like there isn't a lot of benefit to you anymore for it.
Ubuntu can be a bit annoying on older hardware because of the older kernel, but maybe check out Manjaro or Korora. They have both worked well for me right out of the box. Also Korora (or fedora itself) offers this "lab" that has included software for video editing and design: https://labs.fedoraproject.org/en/
I know this is an old posts but I will still share this info for future searchers if you are running OSX 10.6.8 you should be able to find plenty of pirated versions of FCP 7 it may be listed as Final Cut Studio 3. Apple also stills sells this version of Final Cut Pro through its business services department you must call them they do not list it online, and it costs ~$1000 USD.
In terms of Free/open source software nothing is really great or even good at the time of writing this post out side of old versions of Imovie which is still very bare bones and only comparable to windows movie maker in quality.
for Machines stuck on 10.6 or older you are on the last gen of os that supports Power PC architecture and while its still useful for what it was you are still stuck with older predominantly 32bit software.