A trained ear can hear the difference between a $50 and $10,000 violin. A cheap violin is made of cheap wood materials and strings thus quality sound is absent while an expensive violin gives off a crisp and deep sound. The tone quality and projection are far better from high-quality violins compared to cheap ones.
A low-priced violin can be bought in any music stores while prize-possessed violins are usually kept in music museums and extremely lucky violinists can only play those. You can play beautiful music and can keep your low-cost violin for a long time if you take good care of it and make it priceless. No expensive violin can top a loved violin.