Ok - the NFA stamp is a tax stamp and it's presently $200.00... My big question is, who sets that price and how high can it be set?
AFAIK the $200 amount was fixed by statute in 1934, and the statute does not provide any regulatory mechanism for adjusting the tax, other than subsequent action by Congress.
IOW there is no upper limit
, and as pointed out in gc70's post, the $200 amount was originally intended to be confiscatory. One interesting historical footnote is that the NFA reportedly prompted gun stores to dump affected inventory at huge losses before the law went into effect, to avoid being stuck with essentially unsaleable items and having to comply with the new mandates. (IIRC this was referenced in the Heller
decision of all places!)
"OOPS we never adjusted that tax for inflation etc. so it is now $4,000 for each item..."
FWIW according to the Bureau of Labor Statistics, $200 in 1934 dollars is equal to $3,436 in 2012 dollars.
This is one of the fundamental reasons why the NFA is the third rail of American gun politics.