Average

My boyfriend bought these pucks all the time before we moved in together and when he is out shopping on his own, will still grab a pack at the dollar store out of habit. They cost $1- for a pack of 4.
I don't buy these because I don't find them overly effective at cleaning. They give off a bit of a fresh type cleansing odor when you first put them in the back of the tank and that's it, you don't smell the scent again. They turn the water in the bowl bright blue and last a couple of weeks at most. I think they prevent a bit of lime build up, but that's the extent in my opinion. They kind of remind me of product you might find in an outhouse or port-a-potty.
I would not use these if I had pets that had access to the toilet, I am sure it would be harmful if they were to drink it - thankfully I don't need to worry as our Rabbit is not able, nor attracted to drinking toilet water.