A tip from the cheapskate dept.
If you're shooting the sun itself, eclipse for instance, you can use inexpensive welding glass over the lens instead of high-priced filters.
For $5 I got a 4.5 by 5.25 inch piece of #14 welder's glass from a welding safety supply outfit. With the naked eye, you can hold it up to the sun and look directly at it as long as you like. It's big enough to cover the end of any lens I have, and it will take whatever length exposure I want. You just have to be careful to hold it still.
Also, I've used it to take pictures directly into powerful flashlights -- just for fun. Who knows what other kinds of fun you might have!
As for a disclaimer, this is my experience with #14 glass. It also comes in lighter versions, and I have no idea what kind of protection they would offer. The optics expert here is probably a good source on that if you have questions.