I inherited a drink pitcher from my mother. She got it new during WW2. Its not the same pattern as your bowl, but has the same "feeling" of period design. My pitcher is also unmarked. I believe it was a 'premium'. After you bought a given number of boxes of soap or other comsumable merchandice, you could choose a piece of glassware or a plate. There were very few pleasures during the war, but we enjoyed many a serving of ice tea or cool-aid from it.

I'm guessing that you piece may be in the time frame of 1945 - 1952, however, it could be from any time after the begining of molded/pressed glass.

I posted this link a few months ago, when someone else asked about a pedestal punch bowl. The patterns are done in carnival glass, but there's info (and original pricing) you might find interesting.

Here is a link that might be useful: punch sets, scroll down for pics

As a general rule an item is worth about what you paid for it. You could also price similar setsat an antique store or mall. Recently purchased a beautiful leaded crystal large salad bowl for $20.00.