In valuing paintings it is essential to work out who the artist is ( usually from the signature and possibly inscriptions or gallery / exhibition info that may be covered by card or paper on the rear of the painting. Without knowing who the artist is, it is impossible to get any sort of valuation.

Once the artist has been established it is a relatively simple matter to search the internet for works currently for sale or previously sold and also auction records ( although the prices for these are not always freely available )

Around 18 months ago I went to a garage sale of an old house that was being sold for demolition. There was a skip on the road verge with a few old oil paintings poking out the top. I took them home and researched them. One was painted around the 1920's by a reasonably well know artist and ended up selling on ebay for over $700. An old statue from the skip also sold for around $100. The skip was full of vintage decor items, ( most damaged after being dumped ) so I hate to think what else was thrown out.