If you have beaten all 4 Halo campaigns from Halo: The Master Chief Collection, you'll start out with 12,000 Credits to spend. Simply use them to buy abilities, boosters, and weapons before missions and once you spend 10,000 you'll get this achievement.
You also get at least 500 CR for every gold medal, plus bonuses for using skulls and completing Assault Ops. All in all, this should be pretty easy if you plan on actually playing through all the Operations.
If you have excess CR and just want to get this achievement, load up a mission, buy the most expensive ability, booster, and two weapons and then abort once the mission starts up. Repeat about 4-5 times to get this achievement. Otherwise, just play and use boosters naturally and you'll get this achievement by the time you finish the game.