They are fairly inexpensive and pretty easily found nowadays. That wasnt the case 10 years ago when i got this one
....you could only get them from nomadic riendeer herders in northern Finland only if the tribal leader deemed you worthy of owning the sacred ancient Kuksa via the outcome of a wrestling match between you and the largest bull in the herd during rut....(mildly exaggerated).
They can be had for around $20-$30 for a "manufactured" one, and up to $100-$200± for a real fancy hand carved one out of fancy wood by folks such as Alexander Yerks. Well worth the investment in my opinion. Mine is mid grade made out of birch by a guy in the U.S.
They totally change the coffe drinking experience, especially when in the wilderness.
An entry level option is the Kuplika cup. Its made of 50% plastic and 50% wood fibers. They have a pretty cool line of products, worth checking out if you like out of the ordinary