Direct sales are the simplest model. Reserve high-value usernames at launch, then sell them at fixed prices. Instagram has experimented with premium username sales. Gaming platforms routinely charge for desirable gamertags. Price based on length and desirability.
Auctions maximize value for the best handles. When you have a truly premium username like @shop or @gaming, auction it to the highest bidder. This works well for one-of-a-kind handles where market pricing is unclear.
Subscription tiers can include username perks. Premium subscribers get access to shorter usernames. Verified accounts can claim brand handles. This creates upgrade incentive without direct sales — the username is a benefit, not a product.
Partner allocation reserves handles for strategic value. Give @nike to Nike for free in exchange for a marketing partnership. Reserve @company for acqui-hire incentives. Some usernames are worth more as relationship currency than cash.