Joined: Aug 2010
Posts: 12,727
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I do not think I have ever paid more than $10 for a cage. Mine are all metal, not plastic. Several are Blackburn.
Assuming you get a cage for under the downtube, that one should be extra strong. I usually use a small velcro strap on the top of a water bottle in that cage to make sure that the bottle stayed tight and did not interfere with my front fender.