You STOLE that machine for $30. Once you get it all cleaned up and cabinet repaired, you'll have a jewel of a new toy. These old treadles usually have the best stitches as well. My 1910 sews beautiful seams.
I think I need to rent a small Uhaul truck and travel the midwest in "garage/estate" sale season. We rarely get great buys like that where I am.

...and you seem to have acquired the "fold out box" too! (I am sure there is a correct name for that, but I do not know it.) The box was designed to hold various feet. I have my Grandmother's fold out box (no feet left), but my cousin inherited her machine, also a Singer Sphinx treadle, slightly different cabinet.

I've heard it called a "puzzle box".