The really expensive violins are crafted by hand and made over several weeks, even months. The painstaking labor of crafting every inch of it perfectly is what allows it to create melodic tunes that resonate in people's souls.
Recorders made of wood make better sounds as well, which is why they cost times 100 sometimes.
And guitars may require a certain kind of wood and shape (and you might also invest in Martin guitar strings at musicians friend) for a purer experience of music.
So, though one may feel free practicing on the cheaper versions (especially if one is only just learning), do consider investing in the more expensive and better made ones. Who knows, it might just make you more committed to music-making...