I don't give value estimates in dollars on here.Rather,I'll just give you a few things to think about.That red oval is by no means a common sign.Reference books by Wayne and Scott show that the sign is the early version of the oval;1933-1945.
If you cross reference that red oval with their red oval pump plate,1939-1945,and research it a bit I think you will find the pump plate was used in Texas and New Mexico only.So,by extension,that sign probably had a very limited range of early usage.
To a serious Humble collector,or a collector assembling signage of companies that eventually became Exxon,that one would be a hard one to find.It is your sign,value it as you wish,but now you know a little more about it.
