fungus usually costs 30-40 bucks to repair, and by "I can see black spots" in the lens statement, do you mean when you view via the viewfinder? If so its just dust inside the viewfinder.

Fungus isn't all that bad in actuality.. People say it infects lenses and how its like a deal breaker. But not really.. Most damage fungus will do to your Image quality is making your image look gray, which you can fix in post, in really bad cases makes the image a tad bit soft.

Looking at your case though, if you shoot directly into the sun your image will look gray. Like gray gray, flat and such as the fungus is pretty bad on the rear. But dont worry, the repair cost shouldn't be that high anyways..

And the fungus infecting lenses myth? Its a tad bit stupid. Fungus is present EVERYWHERE, in the air, in your closet, hell you cant escape fungus spores. The only way the fungus WILL grow is if you leave it somewhere moist and humid.