If you aim to record an album of cover songs on the cheap, you’ll want to rifle through the resources below.
For the first time in twenty years, a whole year’s worth of copyrighted works entered the public domain in the U.S. on January 1, 2019. Under the terms of the Sonny Bono Copyright Act, works first published in 1923 will enter the public domain, meaning anyone can re-publish them, or chop them up and use them without asking permission or paying the old rights holders.
Want to find the “new” old songs? Go here: 1923 in music – Wikipedia
(NOTE: It’s the written music that is now in public domain, not a recording or video–unless it was recorded in 1923 or earlier–so you can’t use video/audio without paying the rights holder)
Want to get PDFs or video/audio references? There’s a handy site that will sell you the PDF of a song for $5, but the real handy tool is the links to video and/or audio of these public domain songs. It’s at the Public Domain Information Project. A huge list of music with the above-mentioned links.
Want a stellar examle of an album of public domain tunes? Look no further than fingerwizard Charlie Hunter’s album Public Domain. Here it is below: