You reminded me I needed some.

they must fit your head.

ask at the local yarn shop
(not a chain store, a local owned one - they tend to have a table of knitters chatting and stitching)
... or check the calendar of the local libraries for a knitting group (many host them)

... either way, you're bound to find a local knitter who's willing/able to make one for you ....

... us knitters are an eclectic group but always pleased to find someone who wants our stitches....
... a tea cozy should take only 3-4 hours of work for a proficient stitcher

as a rule of thumb;
if you want to pay the knitter; the local going price is double the cost of the yarn - a bit more if it's intricate
(and no, a cozy is not)

alternative - fabric store fleece cut into half moons and bright colored thread/yarn over stitched along the cut edges --
or wool sweater from a secondhand shop felted (or not) and cut to shape
(and yes, you do know how to felt - just wash it on HOT and rinse in COLD)