Well now, as I seem to remember, the quote goes something like this:

 "How to be a millionaire selling player piano rolls:
  Start with two million dollars!"

It really depends upon the type of music.  I imagine that many of
the rolls are pretty ordinary, but of course there might be a few
gems that could even pay for the whole collection.

There are various postal auctions that are possible outlets for
a large collection, and I think that my approach would be to ask
the vendor for permission to catalogue the rolls prior to purchase.
That serves two purposes:

1. It allows some opinion to be expressed by MMD contributors.

2. It produces a list suitable for submission to a postal auction
organiser.

Certainly the breakdown between types of roll -- 65-note or 88-note,
standard player roll or reproducing roll, etc., etc. -- needs to
be considered.  An interesting opportunity though.

Roger Waring - The Pianola Workshop
Solihull, United Kingdom
www.pianola.co.uk