Man, I get so excited when people ask about Filipino literature! 'Sa dakong silangan at mga tulang pasalaysay' is a gem, and while I respect authors' rights, I totally understand wanting to access it easily. The National Library of the Philippines might have digital archives—check their website. Sometimes universities like UP Diliman share public domain works too.
If you strike out there, Project Gutenberg’s Filipino section occasionally surprises me with older texts. Otherwise, secondhand bookstores like Solidaridad might have affordable copies. Jose Corazon de Jesus’ works deserve physical copies anyway—the texture of the paper adds to the experience!