Old Navy: Tankathon – Tanks for $2 and up! 6/25-6/26 This post may contain affiliate links. Please see the full disclosure policy here. Posted on June 17, 2011 Written by Mary Leave a Comment Next weekend (6/25 – 6/26) is the Old Navy Tankathon. Tanks for the WHOLE FAMILY will start at ONLY $2! While supplies last. In-store only. Select stores open at 7 a.m. Limit 10 per customer. I’m going to use my GROUPON for this!!