When I was a student, I could only afford the cheap sheet music in the sales bin in my local music store (no internet, IMSLP or Amazon in those days....).
I was pretty indiscriminate - as soon as I had a little pocket money, I'd buy what I could from that box - any sheet music that looked like real piano music would be snapped up. There were quite a number of easy transcriptions of vocal and orchestral music, which I usually avoided (I prefer to play them by ear and make my own versions).
But the original piano music I found, and amassed over those years soon amounted to a little library of well-known pieces (like Handel's The Harmonious Blacksmith, Rachmaninov's Prelude in C# minor, Chopin's Revolutionary Etude, Grieg's Morning Mood and Wedding Day at Troldhaugen, Scriabin's Etude in C# minor, Op.2/1 - a favorite of Horowitz, Albéniz's Tango, Joplin's The Entertainer, Gershwin's Preludes) and almost forgotten salon pieces by minor Romantic/post-Romantic composers like Paderewski's Minuet in G and Oscar Merikanto's Valse Lente and Summer Idyll (both attractive Grade 4/5 pieces) and Ketèlbey's In a Persian Market. It didn't matter if they were too difficult for me at that time - I figured that I'd one day become good enough to play everything I bought. One can't have too many sheet music scores for rainy days
. I kept all of them in my own cardboard box.
Even today, whenever I'm in the mood, I'll fish in that box, pull out one of those ancient scores (many of them yellowed and frayed, but still otherwise intact) at random, and play from it. The prices marked on them in pencil by the shop owner are still there - 33p for one, 20p for another. Not an insignificant amount for a kid then. Many of them bring back memories of the time when everything was new to me and every piece was a fresh discovery, but I had to play them to find out what they sounded like (no YouTube in those days......).