You can create custom event shops. With items that can give users special roles when redeemed. Well as you can set how much of that item should exist in the event shop, and for how long the role lasts on the player.

Create a custom Event Shop, where users can spend their "Event Points" on custom items you set up!

Interly is an Event Hosting bot, equipped with a full event system. Where you can reward event winners of your server with "Event Points". And they can spend their "Event Points" in your custom event shop.

Setup Event Shop: /create-item /unlist-item /buy-item /view-item /inventory /balance /leaderboard

Economy System: /harvest

Settings System: /add-remove-currency (Reward Event Points or Economy Coins)