Forza Motorsport 7

There is an easy way to do this, and it's similar to the method from Davehx's guide for the 5 Star Seller achievement in Forza Horizon 3.

Buy a 1983 GMC Vandura G-1500 for 20,050 credits

You then need to apply a specific design to the van - search for a design by clicking and type in "Creeper" in the Description box. This should bring up a couple of Mincraft Creeper designs that are well-suited to the van (at time of writing)...I went for the one by chadstrophywife...then apply this to the van.

Then, auction this vehicle (you'll have to make sure it's not your active car by getting in another one after you buy it, as it won't let you auction it otherwise).

You can auction a vehicle by either going to the auction page itself and selecting Start Auction, or from the "My Garage" section, selecting the van from amougst your vehicles and choosing to auction it from the options.

Now set the starting bid at 2K, and the buyout at 23,000K, with a time limit of 3 hours.

Because of the love for Minecraft, this will be snapped up quickly. And you only need to sell one, not five like in Horizon 3!

You can monitor your auctions on the "My Auctions" page - when it's sold, it will have that status. Then, press for auction options, and select "Collect Credits". Achievement will then pop!

What's more, you'll also have made a small profit! Bob definitely is your uncle!

You can easily get both Action House achievements with a second account (doesn’t need to have gold but if the Xbox you’re using isn’t your home Xbox, keep your main account signed in while using the dummy account). You’ll have 100k credits when first starting the game.

Do this with both accounts.

Navigate to Cars and select My Garage. Select the 2019 Hyundai Veloster Turbo (any car both accounts have will work). Choose to Auction the car. Choose the lowest buyout price on the dummy account. Feel free to use the highest on your main. Confirm the auction.

Now back out of the garage and select the Auction House. Search for the car (just change Model to Hyundai). Find the car and choose to Buy Out (shows the seller below the car). Select Collect Car and a few seconds later the Buyer’s Market achievement will pop.

Now with your main, return to the Action House and navigate to My Auctions. Select your sold auction and choose Collect Credits. A few seconds later the Wheelin’ Dealin’ achievement will pop.