My systen is strictly homemade. It is for homemade paper pots or those 6,9,12 plastic seed containers. The water holders are old sided baking sheets. Next, place spacers such as yogurt cartons cut down to 1" height. Top with upside down cookie sheets or plexiglass sheets. Place rectangles of polyester fleece that overlap the cookie sheets and touch the bottom of the water holders. Addwater. I sew lots and use the fleece for various projects and tested.I think I cut 6 'cap mats' from one yard of fleece. I have a five shelf lighted starting setup and have used these for years. No odor yet-wash up in the machine...rinsing with vinegar. For individual pots, I just cut a strip of an old cotton t-shirt and push thru a pot hole and the other end into a water well. Hope this helps. Cella jane ky/6

So I could use discards from the thrift store? Cut down or up an old hoodie?

I got this idea from some violet pots that had a wick that extended down into a water bath below the bottom of the pot. The wicks that I bought from the violet store were very expensive, but when I examined them I was pretty sure they were just diced up shoelaces.

Before starting seeds, put a 3" piece of shoestring through the bottom hole of your seedling pot. Place the seedling pots on a metal wire cooling rack. Set the rack on top of a large cake pan and set the whole thing in a sunny window. Then put about 1' of water in the cake pan. The wick pulls the water into the seedling pots.

Now you're gonna want to cover the whole kit n'kaboodle with some seran wrap and mist lightly every day until sprouts appear. Then you can take off the plastic and the wicks will do the rest. You are still going to have to put water in the large pan underneath them, but maybe only once a week. Cheryl

The cheapest kind of capillary matting is simple jute/hessian cloth or webbing, its biodegradable too :)
Make sure its completely natural, ie it hasnt been treated with anything.