I paid $5.99 for this AGFA filter, and am quite satisfied with its quality and performance. It seems to be well made, the glass isn't loose, and there is a visible coating on the lens, that does not appear to have any noticeable effect on the color of the images.
At the sub-eight dollar level, this filter seems to be a solid buy. Unfortunately the pricing for AGFA filters seems subject to some huge price swings at Amazon. I bought mine from BMG Sales, but when they sold out, the price jumped up to the $30 level. If the cost is in that neighborhood when you read this, you might want to wait a bit and see if it drops back down.
I also had good experiences with AGFA's 77mm UV filter, which only cost $7.99, and was again purchased from BMG Sales. This item, has also been subject to large price fluctuations.
While I normally use Hoya UV filters, I have been impressed by the quality of AGFA. Except for the price issue, I would have no reservations about recommending AGFA. If I were to spend $30, I would buy a Hoya. If you can get this AGFA at a favorable price, you may be very pleasantly surprised.