We have a very old dryer in our rental (not kidding, like 15 years old) and it makes so much loud noise. It also leaves black streaks all over our clothes.
I have never had to buy an appliance before, so I was wondering if anyone has insight as to whether it is smarter to buy a new (although cheap) dryer, or try and have it fixed?
Since you are renting, you should talk to your LL about getting a new(er) one. I highly doubt a dryer that old can be fixed - the parts are probably impossible to get by now.
I would also NOT recommend you buy it yourself, unless you plan on taking it with you when/if you move.
Unless it's a commercial dryer, I doubt you'll be able to get parts. I would ask your LL to replace it first, as the black marks are kind of a big deal. If they won't, just buy a used one off of Craigslist. Fixing appliances anymore is very expensive, and it won't solve the issue of the marks on clothes.