I'm glad to see you're still out there diggin' away. But I hope when you say "oldest" you don't mean oldest bottle ever found. Your Coca Cola "Fresca" bottle is from the 1970s. Not to say it isn't collectible, because they are. I was just wondering exactly what you meant by "old?" []
Here's a website about "No Deposit" bottles. Check it out! It doesn't necessarily give values, but I think your Fresca is shown on it - plus there is some other interesting info - especially by clicking on their "History" option.
Nice find. These No Deposit/ No Return bottles are coming quite collectable now. As for your Fresca; its a rather common one but with a crown top, that may help the value of it considering most people like the crown top NDNR bottles rather than the screw top ones. I'd say value is probaby about $3-$5 maybe a bit more if someone really wants it. Nice find and keep digging.