Knex Sale – Dinosaurs Building Set only $17 shipped! Great Christmas Gift idea! August 22, 2012 by SMFM Leave a Comment Knex Sale- If you have a child who likes K’nex here is a Groupon you may want to grab! You can get theÂ Kâ€™Nex dinosaurs building setÂ from Groupon which is only $14 + $3 shipping. Great gift to put away for Christmas !!! Check out the Knex Sale Here!