Do you have the serial number or model number of the machine? You may already have the info you need but the following may help you.
The following site will help you figure out the model number and the date it was allocated.
http://www.singerco.com/support/serial_numbers.html
Depending on whether the s/n starts with a single letter or a double letter you click on the appropriate link. That will take you to a second page which on the right has the beginning letters. Click on that and it will give you the information you need.
To find out if it is a good price, try asking on the post on this board "Vintage Sewing Machine Shop". Billy, Charlee and others are excellent about helping. I shipped a sewing machine in a case from NY to TN for under $35.00. Ground shipping!
Hope this helps!