i ordered three of the cheapo $ 29.97 telestocks from Sportsmans Guide.  There's a bit of rattle, but not nearly as much as with the original equipment aluminum atrocity on my formerly pre-ban Eagle Arms AR.  

But that's not all.  Two of them functioned properly, but the third would not properly lock into place.  Put a bit of pressure on it, and it would collapse.  But as it happened, I had a spare telestock.  So I took the plastic part off the buffer tube (or stock extension, if you prefer), and swapped it out for the other one I had on hand.  It worked fine.  

Bottom line--For about $100, I got two complete and functiuonal telestocks, plus one complete buffer tube assembly.  I've paid more than that just for the buffer tube assemblies.