I have not seen one of those in years. The Bill Dance Advantage Lure Retriever is the other one you described and they aren't worth the money, IMO.
I made a plug knocker out of two 3/4 drive deep sockets with some washers inserted for added weight plus an I-bolt to hold it all together. A little nylon twine and a marker bouy to wrap it around. Works great.
Some of the old, small window weights work well, too.
"Things turn out best for those who make the best of the way things turn out" - Zachary Troy Schrah - a young man with vision far beyond his years.