Um, try knifekits(dot)com. .080 or thicker kydex and their hammer rivet kit. For bare minimum budget. closed cell camping pad (the blue ones) some plywood and clamp or 2 and you got a press, or use a pair of pot holders.

The web has free tutorials for kydex, just look (not great tutorials last time I checked but, get you started decent ones).

The price you want and quantity lean towards a do-it-yourself type ordeal. You will need 1-2sq feet of material (less if you do not make belt hooks/loops out of the scraps).

Do not heat over 350degF or toxic fumes will be released and work in a well ventilated area. wear some gloves its 350deg when you pull it out of the oven.

You can make other gear holders with it as well. Although you tend to use different foarming items to get the shapes you want.

In case you could not tell I do some of this stuff on the side. Actually I got 3 sheaths I am working on this weekend, 2 for customs and a 1 production blade.