I have no idea how much one dollar was worth at the time the movie is set in, but her third customer around 5 min into the movie paid 5 $ which seems very inexpensive regardless of what kind of service she provided.
Any suggestions what she could have been offering for that price?
Probably not the full shebang, but it could of been a starting price, and the fee raised after negotiations were made.
"Getting old is not for sissies."
Bette Davis
In the 1960s, a dozen eggs cost around 50 cts (45 to 55 says http://www.thepeoplehistory.com/60sfood.html).
Today, a dozen eggs is about 2 USD (between 1.6 and 2.3 says Bureau of labor and statistics : http://data.bls.gov/cgi-bin/surveymost)
So that's 4x the cost. That $5 in the movie is now already $20. Which is still cheap, but could be an appeal price.