Prices start at £5 for attendees under 12 years old and increase to £10 for those aged 12 and over. A GAME reward card is required in order to purchase tickets.
Announced at the Video Game BAFTAs in March, GAMEfest will run from September 16 to 18 at Birmingham's NEC arena.
"GAMEfest is really shaping up as the place to be to get first hands-on with the titles coming out before Christmas," said marketing director Anna-Marie Mason.
"We're confident that gamers across the country will snap up the tickets so they can play before anyone else the most anticipated titles of the year."
Sony, Nintendo, Electronic Arts, Disney and Sega are some of the publishers who will be exhibiting games at the expo.
Microsoft has been announced as a sponsor for GAMEfest, and will show a playable version of Gears of War 3 several weeks before its worldwide launch.
Eurogamer Expo organisers have said that they are "disappointed" by the timing of GAMEfest, which is scheduled to run less than a week earlier.