Most Effective $20,000 Budget

$20,000 Budget for a large Minecraft Server

Ads

$5,000 - Win 1st place on a minecraftservers.org auction. This will advertise your server for two weeks and will get you a constant stream of players

Graphics
$500 - opgraphics.co is a website that provides the best Minecraft banners. Normally you're going to spend $300 on a high quality banner, but just tell him you want him to make the best banner he has ever made, this will increase the effectiveness for the minecraftservers.org slot

Development
$1,000 - Spend this much money on a plugin that is custom and unique, has unique commands that prove it's your server, for example I have /vw request, etc. I would say that for $1,000, you should be able to get someone who can code a plugin with 150+ custom enchants that are all unique. You will have to think of ideas, but it will be worth the wait.

$3,500 - Spend this much on small YouTubers. You should charge $10 per thousand views, ALWAYS. And make sure that they don't bot. You can check by subscribers driven

$10,000 - Spend this on multiple large YouTubers. I can get you connections if you want.