There was a link a while back about replacement panels for the harbor freight greenhouses. I found this place that has small panels and cheap shipping. The 2x4 panels that fit mine are about $15. Shipping for two is $8 which is about what I would pay in tax if I bought from Harbor Freight. I haven't contacted Harbor Freight yet for what they charge. Oddly enough, their 8mm panels are cheaper than their 6mm panels. Go figure.