Would be a bad idea to buy the iphone 4 now?

I can't afford the iphon 5/s, but I did initially want the a samsung galaxy first. Anyway, I like to watch movies, listen to music and generally surf the web a lot. I also like to download a lot of apps and take pictures. Would the iphone4 be significantly inadequate now.
If it helps I'm 18 and my parents can't afford and think it's morally incorrect to get me a iphone 5/s, but I'm not complaining.

Nah the iphone 4 is good don't worry about it so much

It wouldn't be significantly inadequate, if all you want to do is watch movies, listen to music and surf the web, it should be fine. While there were a few hardware changes to the iPhone in the next gen, it shouldn't be so great as to cause a lot of apps to not be compatible as long as the latest iOS is installed.
This is something you'd probably have to do upon buying the phone and setting it up, installing the latest iOS to ensure you can get whatever app you wish.
Otherwise it should be fine.

If you get a new one for free then fine. It really comes down to get cost and condition. The iPhone 4 fan do these things as well as it could in 2010 when it just came out.
One possible problem - Apple updates the iPhone OS at least once a year and not every device will be able to get the update (or all the features of it). The iPhone 4 can get iOS 7 but not all of its features. The older iPhone 3GS can't get that iOS version at all. At some point there's going to be an iOS update that WO t work on your iPhone. Your phone will still run fine. It won't be able to gwg apps that require the new iOS. Some updates for apps that works fine on your old iPhone may also require the new iOS. It's very possible that you may go a year orbtwo without noticing that yij Canot get the newest apps. It really depends on how you use your iPhone. I don't have an iPhone. I do have a iPod Touch 3rd gen that's stuck at 5.1.1 but that's fine for me.

Buy a iphone 4s its jus a bit more expensive den iphone 4 but the iphone 4s way better den the iphone 4

I wouldn't personally but it isn't a bad idea.
it runs iOS 7, all the apps, etc. Would be fine for your needs.

Buy a iPhone 4S maybe, but not the old iPhone 4. I have no Apple hate, but the cameras in iPhone's are far behind the Samsung's & the other Androids.
Sadly you MUST buy what you can afford, do buy the best you can no matter what that indeed is. I myself have a cheap phone, a used HTC Wildfire S (on t-mobile) which I got a great price on eBay $39 USD… Cheers.