redturtle, your 99 looks like mine, except that I see a white foot petal in back of the machine, or at least that's what I think is there. The hole in the front of the bottom of the case is for a knee bar, which mine has. But yours probably has been rewired to use the petal, is that right? Mine is a 99-13, meaning it has the knee bar.
OK, now I need help. I bought some 66 bobbins from a sewing machine repairman, and they were a bit much, $1.00 each, or so I thought when I saw the Singer 66 (metal) bobbins at Walmart at a price of 4 for 97cents or something like that, under a dollar. I went ahead and bought 4 package. I used one of the Walmart Singer bobbins and wound thread on it and put it into the bobbin holder, but it won't go around easily, it wanted to stick. I then tried putting the ones from the repairman in and they twirled around without sticking at all. (I used a pin in one of the holes to twirl it around in the bobbin casing. I tried all of the rest of the bobbins in the W S package, and they stuck like the first one did. I didn't open any more of the packages, as I thought they'd be the same. Has anyone else had this problem too? If so, where do you get your bobbins? Thank goodness I saved my receipt so I can take them all back to Walmart.