Well, you can actually purchase just the lids and put them on a glass jar you already have ... whatever size works best. I usually use a quart jar. You can order them from Sproutpeople.net or Amazon.com. I'm not advertising for either of those sites and I don't make any money off the sale of their sprouters or supplies, so that's my disclaimer. :)
Health Food stores usually carry them as well as some grocery stores sell just the lids in the kitchen gadget section. And I think Walmart may carry them.
Here is what the lids look like:
https://www.amazon.com/dp/B000N8MRW8/
Your best bet for an entire tray set-up if you want more than the lid is a Health Food store.
