Got this brand new Swagman bike box off eBay for $25 shipped. It will be perfect for commuting to work. I can put my work clothes into the box and keep them from being squished, and keep them dry and clean as I ride. It was very easy to install on top of the rack, only took a few minutes. The box has 2 clips on each site to keep it closed, and also comes with a lock (which I won’t need).