Cost is only one of many indicators of how good something is.
Having said that, like many things in life unless someone is totally screwing you typically get what you pay for.
If you can't tell the difference between a $200 or $2,000 or $20,000 DAC then you've either been blessed with poor hearing and won't suffer from upgradeitis or you need to work on the rest of your system so that you can realize what a difference a great source can make.