Football Manager 2020

Really easy achievement, that will also double up with the one for buying a player if you do not already have that. Obviously you can do this by playing naturally, but many teams you might want to play as don't have that amount of money and won't for some time, so this will speed things up for you.

Start a new game as Manchester City (England, Premier League) as they have a starting budget of roughly 47 million. Start on the "Late Pre-season" setting, this isn't essential but will save a lot of time. You can skip over the introduction press conference and meetings, as that isn't important for this achievement.

First, go to the transfers tab and then "adjust your transfer budget" by increasing the transfer budget by 1 slide (so your Budget is now just over 50M).
Then, go to the Scouting-Player Search area, and sort by most expensive players. It doesn't matter who it is, although it would be better with older players as the computer is less likely to inflate their price. If they ask for more than 50M for the player, try a different player. When I did it I bought a player listed as 41M and increased his transfer price to 50M exactly.
Then when it comes to contract negotiations, just accept any offer they put on the table, I believe Man City's wage bill should cover it for most of the players.
Then keep advancing till the transfer is completed and then 1 (or 2) achievements are yours.