If what I am reading on the following links is correct according to how I am reading it, your machine would appear to have been made about June of 1910.
http://www.singerco.com/support/serial_1letter.html and
http://www.singerco.com/pdf/SINGER_G_nos.pdf When you click on the first link, you click on G Series in order to get the pdf file. It's kind of hard to tell what the exact model would be.
I don't think that there is any sort of "value range" because of the condition of the machines. It really depends on what someone is willing to pay for it in order to determine a monetary value of some kind. Certainly, if a machine is cleaned-up, serviced and the cabinet repaired/refinished, it would be likely to be worth more money. Many of the old machines are still quite usable for sewing. Oftentimes, the speed of a treadle machine is desired because of the kind of sewing that is to be done.
A lot of people will say that old treadle sewing machines don't have much "value" because they keep showing up in garage and yard sales for very low or even give-away prices. However, old sewing machines can be usable and also act as a conversation piece in a home. Many of the cabinets on them are incredibly beautiful in their design. A person could decorate with items around an old treadle sewing machine that might be of the same period of the machine to create a nostalgic atmosphere