The short answer is . Unlike the original game, which is "freeware," Doki Doki Literature Club Plus! is a paid commercial product.
Released in 2021, DDLC Plus! isn’t just a simple port of the original 2017 cult classic. It is a premium expansion that includes: Doki Doki Literature Club Plus Download Free
If you see a site offering a free download of the Plus! version, proceed with extreme caution. These files often contain: Malware and Viruses: Designed to steal personal data. The short answer is
DDLC Plus! frequently goes on sale during Steam's seasonal events (Summer/Winter sales), often for a deep discount. which is "freeware