There are differences between equipment, but as long as your equipment goes loud enough and meets a certain basic standard, they are pretty insignificant. Very cheap equipment can have poor SQ, but it's not necessary to spend a lot of money to get good sound quality these days. Most people agree that a Sansa Clip+ (U$35) is pretty ****ing good, and the measurements confirm that. If you pair that with some Klipsch Image S4 in-ear phones (U$45) or Koss Portapros (U$35) which also get very good reviews, you will have a combination which is very hard to beat at any price. You certainly won't have any reason to feel that there is some musical pleasure that you are missing out on. Any improvement you can get will be absolutely miniscule, and the difference is so small that anyone with normal hearing and taste can easily ignore it. After all, you can enjoy a track you like, played over a supermarket public address system. Just read the reviews to find out what's what.
It's nice to spend money, it's nice to have expensive gear, but it's only jewellry when it comes right down to it. I have lots and lots of equipment, computers (3 PCs, 2 laptops and a Raspberry PI), soundcards (4), DACs(2), players (CD, DVD & BluRay), DAPs(2+ a phone), solid state amplifiers(10?), tube amps(2), speakers(3 pairs), headphones(5?), but I don't kid myself that I bought it or built it because I needed to, to get sound quality. I just like gear. I'm a gearhead.
More than that though. I play guitar, mandolin, penny whistle, harmonica and a bit of keyboards, and I can make a stab at a few others. I enjoy music.
Don't take any wooden nickels.