To buy some rennet I found several choices:
I currently live in Katy, a suburb of Houston, Texas and looked in local branches of two large USA grocery chain stores called
Kroger & HEB in cheese and pudding sections but no luck. Also tried Sugarland Texas branch of large USA & Canada grocery chain called
Whole Foods Market where I found Malaka brand vegetarian Rennet for USD4.99 in the refrigerated cheese section. Pictures of this product below. My 1/4 oz eye dropper style bottle says it expires in 5 month from when I bought it and store in fridge.
Also
link to Whole Foods Market's info webpage on Rennet & and Coagulating Enzymes.
June 13, 2008 Update: Completely used this rennet after cheesemaking from 12 US gallons of cow's milk. Works out at USD0.42/1 US gallon of cow's milk coagulated, very expensive. Found best at 25-30 drops per 1 US gallon cow's milk vs package directions of 20. For my second rennet
I bought this one at USD0.04/1 US gallon of cow's milk.