According to this, a T inside an inverted triangle logo was used by the Turner Glass Company from 1910-1929. Being a perishable product, it's tempting to think that 318-29 is the packing date (day #318 of 1929, i.e. November 11th). I can't say that for sure though. If it is indeed 1929, that's in remarkable condition for being almost a hundred years old!
The World's Fair was held in St. Louis, MO once, in 1904 (source).
I'm not a collector so I can't speak to the monetary value (as my username suggests, I just dig stuff up in my yard) but I personally would be excited to find something this old in this good condition.
