In 1961 Harvey N. Roehl wrote [in "Player Piano Treasury", page 48]:

  "The 1912 Welte-Mignon roll catalog of several hundred numbers lists
many rolls costing $10, $15, and up to $17 each, and some much more,
considering that very often compositions had to be divided between two
and three rolls owing to their length.  Little wonder that today these
original German-made Welte machines are scarce.  Not many people could
afford them in their day, and those people of means who could do so
undoubtedly were the types who could afford to discard the instruments
as soon as they (became) tired of them."

and [page 49]:

  "As in the case of the Welte, this also meant that only the wealthy
could afford reproducing pianos, and that the market was always bound
to be a limited one.  But rolls were made for much lower selling prices
(a Duo-Art roll was high if it brought $4) in an attempt to capitalize
on the possibilities of this part of the market."

Can anyone provide me with an estimate of what these dollars may be
worth in US terms today?

Grahame Code
Australia

 [ That was the era of beer for a nickel, so for the cost of 200 mugs
 [ of beer one could buy a $10 music roll -- a sobering thought!  ;-)
 [ -- Robbie