Fans can purchase individual tickets at £20 for adults and £15 for the under 18s and get the adjoining seat of the same value entirely free of charge all day today online at www.wru.co.uk/tickets via telephone on 02920 230130 or by calling into the WRU's Cardiff Arms Store.
On matchday tickets will be on sale at Cardiff Rugby Club ticket office and the Ticketline shop on Westgate Street from 9am until kick-off and ticket collections will be at the WRU's Cardiff Arms store.
Millennium Stadium Manager Gerry Toms said: "There has been record interest in this summer's home internationals and ticket sales have been busy all week following our win over England last Saturday."
"Wales v Argentina will be a great day out for families, with the traditional 2.30pm kick off time and the family-friendly ticket promotion but my advice to everyone is don't leave it too late. Whether you are collecting or purchasing tickets please do so early in the day. Do not leave it to the last minute or you may well find yourself waiting in a queue and missing the start of the game"
Tomorrow is the last opportunity for rugby fans to send Wales on their way with a resounding cheer before they take on South Africa in their opening RWC pool match in Wellington, New Zealand on September 11.