The Pubco has teamed up with some of the UK's biggest drinks producers to run the promotion in a bid to boost pubs sales this January.
It is the second year the company has run the deal and this year it has been widened beyond beer to include gin & tonic and soft drinks, as well as low and no alcohol beer.
Around 1,000 Ei pubs will be running the bounce-back deal for their customers from January 2 to 20 2019.
Customers will be able to track the pubs taking part and redeem their free drink via a web-based app and a dedicated website, which will be supported with its Cheer Up January campaign across social media, online advertising and PoS.
The partner companies, which include Molson Coors, Heineken, Diageo and Britvic, will also be promoting the initiative through their own channels.
"January is a notoriously challenging month for pubs so we wanted to do something that supports our publicans and helps them drive footfall during the post-Christmas lull," said Helen Cook, customer director at Ei Group.
"Our aim with this initiative is to remind consumers that the pub is a great place to socialise no matter what time of year and help beat the January blues. We know that people want to cut down after the indulgences of the festive season so we are delighted to have extended the offer this year to include a broader range of drinks that makes the offer more accessible to more people, including those who want low or no alcohol options."