If I pay the composers/arrangers I like, is it ok if I don't pay the composers/arrangers I don't like?
I don't want to take this thread down a route that's going to be a dead end. Nor do I want to appear to be jumping up on some moral high horse. All the same, I've seen people I know have their work pirated, copied, and re-used, to the extent that of hundreds of copies of their work that have been used, only three or four have been paid for, and in some instance, the copyright pirates have been commercial outfits, making profit from the labours of others, and relying on the difficulty and costs in many jurisdictions of prosecuting a case under copyright legislation. One wouldn't normally go around supermarkets, picking up the produce and eating it, then deciding not to pay because one doesn't like the taste. Nor buy a newspaper, then take it back for a refund because that day's news was depressing. It would be unusual to go to a piano recital and decide not to pay for a ticket in case you didn't like the interpretation. There are some publishers, as has been pointed out, who will allow a sample page or two to be downloaded, to allow the prospective buyer to get a flavour before purchase. Copyright infringement is not an appropriate alternative to 'try before you buy'.
The OP's enquiry appeared to assume, quite innocently, that there was such a thing as R&H material available without copy restrictions. That isn't the case, and it's perfectly in order to give guidance to the OP about this.
There is no shortage of material that is truly out of copyright, for pianists of all levels. If you ran a taxi service, only for your passengers to default on the fare, how long would you want to stay in the taxi business?