I go snorkeling for bottles quite often and find some weird stuff. I recently found these two coca cola soda water bottles. When are they from, how much are they worth?
It would appear from closed and sold listings on eBay (listings that actually ended in a sale) that your bottles are worth in the range of $5-30. If you browse the sold listings, you will find that collectors look for the city and state markings. Some are harder to find than others.
And the usual criteria also apply - condition esp. is quite important to value.