The first thing you need to do is complete the game and unlock WCX from the Extra Content shop.
Then In the new game plus, you have to meet with merchant to buy WCX, which will also enable you to buy the recipe for Rifle Ammo.
Make a Rifle ammo, go back to the shop and sell this Rifle ammo, this should get you a 7 in the final position of your money amount.
Then what we’re going to do is sell our handgun ammo in order to get a 7 in the penultimate position. now we have a currency tail of 77.
Then we’re going to make some big purchases to get rid of anything greater than 10 000, and remember, always make a save point next to the merchant so that you can revert to your last save and you don’t have to keep your purchases.
After you only have a little bit of currency for the last step, you need using Handgun ammo for the third to last position.
Now we have 777 to grab the achievement.
