The Lifeline program is still available. The way they explain it is confusing, but the “discount” covers the complete cost of service for most Lifeline providers, so it works out to free. You just need to be receiving any federal public assistance – Medicaid, food stamps, TANF, anything.
ACP was more of a broadband program with phone service attached, Lifeline is more of a phone program with some data attached. If you happen to have an unlocked phone, many lifeline carriers support bringing your own device to some extent.