George de Brush is fairly well known. The painting "Silence Broken" is shown here among other work.
He has his own article in Wikipedia:
From time to time unframed collections of prints can be acquired at auctions such as are held by Somerset Auctions.
I myself purchased a lot of 100 such prints, both of master and lesser known works, unframed, on fine acid-free art paper, properly prepared and treated to prevent aging. Typically in wholesale collections these prints are can be had for $10-$25 each in lots of 50 or more.
BUT these are not signed prints, and they are not framed. An authentic signed print is naturally more valued by collectors, and framed prints are naturally valued more by retail customers.
The following link shows a retail offering of various prints, priced at $100 or less (prior to custom framing):
Let me know if you want more links of a similar nature.
When my mom was involved with the Oceanside Art Museum years ago, the value of prints was often discussed. Based on what I learned from her, and from the wide availability of prints, here is what I would estimate the value of your signed print at:
The print itself: $100 - $200
That it was hand-signed by the artist more than 70 years ago: $200-$300
If it is custom framed: $100-$150:
So my estimate of value is $400-$650. If you can find the "right" buyer for the print, someone who appreciates both the artist and the historical value of a signed print, you may be able to realize near the high end of that range.