50 cents?? Sellers throw that stuff in the garbage can at the end of the day if it doesn't sell. You would have given it a good home I bet. There are a lot of ways to calculate and compare the 1920 dollar to the 2011 dollar and it depends on how you do it but, roughly, it would take 25 2011 dollars to equal 1 1920 dollar.
In other words, if you could hop in the time machine and go back to 1920 or so to buy yourself a brand new $2 Mossberg ratchet, you will need to take 50 2011 dollars with you. The reverse of that would be, if the original owner wanted to hop in his time machine and travel to 2011 to get his Mossberg ratchet back at the price you saw it for, he only needs to bring 2 1920 pennies with him.
Careful, this kind of thinking can cause the brain to overheat and possibly do permanent damage.