Purchasing "Nitro" Memberships in Bulk for Giveaways

There are a few Discord channels that I am a part of that has between 1,000 and 4,000 members.

I was feeling a little generous and wanted to purchase 10 Nitro (month long) memberships for both of the channels (total of 20 nitro memberships) to randomly select from the latest active users (by activity or time?) by using the @ for being selected and I guess private message for the redeem code.

I don't know, it was just an random idea that got me excited to reward users and I'm to lazy to manually make 20 single purchases, and then figure out how to grab a list of the channels members and then find a app to do a random drawing.