Hi, welcome to TFP!
the tf 100 is available at
TFTestkits.net and on the west coast at
Pool Supplies, Spa Supplies and Parts
Those are the only 2 places you can get the TF100
the K2006 is a great test kit and lots of folks here use them. There is a version of it K2006
C. The "C" version has larger quantities of test regents, which is nice, so that you dont have to order refills as often.
Of the two, the TF100 is the best bang for the buck because the test regents you will use most are double that of what is contained in even the "C" version of the K2006.
Hope this helps,