The build cost of the TC is $3200 (160% of War Factory cost).the TC itself only costs about 400 (dont calculated the price yet)
4 Minigunners + 4 Tank Hunters = 4x300 + 4x325 = 1200 + 1300 = 2500
3200 - 2500 = 700
So, TC actual cost is $700. Thus we have a mobile prop tower at the cost of $700.
However, $3200 is a huge money for a weak unit which the troops inside can't survive when the TC is destroyed.
I propose that its cost should be reduced along with the number of starting troops inside.
2 Minigunners + 2 Tank Hunters = 2x300 + 2x325 = 1250
1250 + 700 = 1950
700 is a bit too expensive for unarmed lightly armored mobile prop tower. Here is my suggestion.
700 - 50 = 650 >>> 650 + 1250 = 1900
$1900 is much more affordable price and you might give player an option between fully-loaded or half-loaded TC.