It's a very pretty machine. If you want it for a decoration, it looks worth it. But if you want to use it, then sit down and test it. Make sure it has the shuttle bobbins (they can be hard to find) and the gears all work. Sewing on a treadle is so much fun. (Plus you feel like you are getting a little exercise at the same time. LOL). Since the lid is missing, maybe try to negotiate the price a bit. Many years ago I was ready to buy a White treadle for $190.00, I went back the next day to buy it and the store was empty. (Thought I had imagined it - so asked the store next door and they said the came in the night and removed all the inventory - it was an antique store and it was full, so everyone was surprised.). Told my grandmother about it, she said, "Why do you want to buy one when I have 2 here at the house." She lived in Kansas, so I took my girls back and I was able to bring one home. I brought the one that had the instruction book - so much fun! When I hand sew a quilt, I use it to put the binding on. I read once that it was still considered hand made if you use a treadle.
Hope it all works out for you.