Microsoft did tease that Killer Instinct would be available to buy as a full game if you'd rather avoid its free-to-play model, and it has taken the wraps off of one way to do just that. The physical 'Pin Ultimate Edition' includes all eight characters from "season one" and a load of extras in a limited-run case.
The set is available for pre-order on the Microsoft Store for $59.99. It notes that some of the eight characters will be made available after launch, but you'll get early access to all content from the first season. You'll also snag all of the costumes and accessory packs, and the original Killer Instinct arcade game.
Finally, it includes two collectible pin badges (Jago and the Killer Instinct 3D logo) designed by Penny Arcade--hence the name. More pins will be coming as part of promotions for a total of 16, and this set includes a folio to put them in. The announcement teases that every month a new pin will be revealed, and you can earn them "through your community and in-game efforts."
The characters are being priced at $5 apiece, so getting the eight of them included makes up $40 of the cost by itself. That makes it a pretty decent deal if you know you want all the characters, as long as you'd like some of the extra chotchkies too. Keep in mind that season two will bring more characters, and this set doesn't include them.