One dollar bill with a blue star next to the serial number. It's a 1957 B series

If used, about $3.

Buying or selling? If you buy its going to be more than $3 Amazon.com: US Currency 1957 B $1 Star Silver Certificate: Everything Else However, selling you should be happy with the $3

From what I found online, it's worth around $2.99 if it's in new condition. If it's in less then new condition, you're looking at closer to face value, which is $1.00.

Sadly, there's not a lot of money to be made in old bills unless it's very rare and very old.

I collect coins and bills. I went to sell some of my rare coins to a coin dealer, and even the rare ones from the 1800's weren't worth much. The ones made of silver however, they were more valuable. But, I was still looking at only around $10 a coin, and those were silver and over 100 years old.

For a paper bill, only 50 years old, you won't get much. In fact, I'm surprised that they're selling for $2.99.

Look for a coin and bill collector in your area. That would be the best person to ask. :)