Save your money, clean and oil it yourself. You can download a free manual if you don't have one from Singerco.com under the Resources button. It will show you all the oiling points. Your first cleaning can take a couple hours if it's really dirty and you're really thorough. After that routine cleaning and oiling only takes a few minutes. Read the sticky on cleaning these old machines and watch Muv's videos. It's well worth the time. Singer oil is good. So are other brands of sewing machine oil. A favorite here is a synthetic light oil called TriFlow. Most oils not made specifically for sewing machines are too heavy and will gum up your machine.
Congrats on your 99! I have a real weakness for them.
Rodney