Red Sylvainia Phone Radio

I don't know anything about vintage radios, but this one was in a box of stuff I bought at an auction. I like it and it works so I'm hoping somebody might tell me what type plastic it's made of and what it's worth. I Googled and found an old ad indicating it was made in 1956 and sold for $42.95, which seems pricey for 1956. Many thanks for anyhing you might tell me.