Look up E-jen fermenters. There is a video on Youtube about them by Livart. They are plastic with a inner lid to keep your veggies under the brine. Most Korean markets sell them but they are not cheap. Ive seen a 5.8 gallons on Amazon for just under $40 and a 11.8 gallon for almost $70.
I wasn't sure if its ok to post a direct link since im new here.