How can I see/visit Chernobyl? Is it expensive?
Technically no, it's still an area that's off-limits from the general public. The majority of people who do go there, are likely urban explorers who go there illegally. You can take tours near the area, but not close to where the accident took place. Just places that aren't as radioactive and dangerous.
You can take tours in certain area's near Chernobyl, but I think it's mostly cut off from people. I hear they have guards trolling the area to make sure no one tries to sneak in, as it's very dangerous. It's not only dangerous for the person breaking in, but they could track radiation out of the area, and I don't think want that either.
I think you can even take virtual tours these days, though I'm not 100% sure on that. I would imagine there being virtual tours due to the nature of the disaster. They may also have museums in the area that are devoted to mostly Chernobyl related items.