With my limited audiophile experience, this is my take :
*generally* speaking, you get what you pay for. If Product A ($100) sounds as good as Product B ($500), do you tink the manufacturer of A will sell it at $100? [of course we will get into a heated discussion of what constitute "good" sound...but tats a different story :-D]
Secondly, there's the law of diminishing returns. Hence a $500 product, tho sounding better than a $400 one, may not be worth the extra $100. Again tats subjective and highly dependent on the "I want" factor vs affordability.
If money is no object and you simply buy the best there is (assuming there's such an option), then IMHO you dun get to enjoy the joy of this hobby. For a start, i would suggest buy what you can afford first. Move on from there, coz music/equipment/taste develop and change over time, not to mention affordability...and tats what makes this hobby so addictive. :-)
Hope i'm making sense...LOL