Jeanne, here is where you can download a manual for your Singer 99
http://www.sew-classic.com/uploads/99K.pdf
You can print it 2 pages on one piece of paper and it is large enough to read. The original manuals are small and less that 1/2 the size of a piece of printer paper.
Your machine is a 'low shank' machine and can use almost any 'low shank' attachments. Are there any coming with your machine? Mostly you will just need the regular foot that will come with your machine, but it is fun to get some of the other attachments too. I can attest to that!
Here is where you can find out when your Singer was allotted, how many were in the allotment, and the model of your machine. It is not just for the featherweight 221 machines. I like this site the best for dating Singers.
http://thefeatherweight221factory.co...alNumbers.aspx
Janis