Rusted Proto-Drake is a reward from the Dungeons & Raids achievement Glory of the Ulduar Raider (10 player). This mount can be purchased through the Black Market Auction House.
Here you can buy Rusted Proto-Drake for EU or US Servers.
You'll get guide for getting Rusted Proto-Drake
You'll be able to get Rusted Proto-Drake
Additional budget for Character transfer or Character boost to max level. BMAH Services in Shadowlands now requirement to have a max level character on server, so Trial character will not work.
Free time on evening, if you choose selfplay option