Vintage rings offer a much wider variety of designs than you can buy in your local jewellers and the fact that they have already lasted a fair amount of time shows that they are probably well made.
The best places to search for vintage rings is in antique markets and also thrift stores, they may be in bad condition in some cases but you can always have them restored or even have a new ring made based on the original design.
Its also worth looking for vintage rings online but it is more likely that the dealers will know what they have and charge accordingly, of course sometimes you will find a ring that seems great value because it isn’t to everyone’s taste but may be perfect for you.
If you are looking for a unique ring for yourself or as a thoughtful gift then vintage rings are each something you will probably never see again, in many cases older antique rings would have been one off pieces to begin with.
Vintage rings often keep their value as well as you will still have the value of the materials including the metals and stones, though this does mean that a ring made with gold with large diamonds set in it is unlikely to be sold at a bargain price in the first place.