Mobilesheets pro as advised is a great way to access a big music collection.
I have a big collection of music in books, built up over many years, and probably even more on various discs and pdf type downloads downloads.
Using a laptop or pc monitor in easy view of the keyboard is a great way to help with playing and learning from like the PSR tuition sections. I have an old PC and 21" monitor that I use just for my music, running Windows 10, it cost me very little (£30 ) from an office clearance sale. there are plenty of good cheap units about if you look. You do NOT need a brand new laptop or pc to run most music programmes. Only the professionals can justify using that sort of software, or can even afford it, as some are extremely expensive.
I use a programme called SCAN SCORE. It's a German produced programme which allows the user to scan direct from printer and load any sheet music straight into Windows or Mac, and from there you can edit it read it transpose it, and even play it from within the programme just by hitting the play button in the programme, without using your keyboard. So it's completely standalone as far as playing goes.
It's NOT free, but it does come in various levels, so that if, for example you're only reading the music or composing for a single or a few instruments, there are cheaper versions. I have the ENSEMBLE version, because my wife is in a choir, and although our musical requirements are different, it's all music, and helps us a lot.
I've found it immensely useful, and it's worth a look.
