Forza Horizon

Here is a list of Ferraris that are available to you in the game (i.e. not DLC). There are 16 total, just enough to earn this achievement. Cars that are worth 1,000,000 Cr or more have the price listed next to them (for the "It's Just Money" achievement).

1957 250 California- 3,000,000 Cr
1962 250 GTO- 10,000,000 Cr
2009 California
1957 250 Testa Rosa (Barn Find)
1984 GTO
1995 F355 Challenge
2011 FF
1987 F40 (awarded for winning the Bi-Plane Beatdown Showcase event)
1995 F50
2011 458 Spyder
2007 430 Scuderia
2002 Enzo Ferrari- 1,300,000 Cr
2010 599XX (awarded after beating Darius)- 1,500,000 Cr
2005 FXX- 2,500,000
1989 F40 Competizione 1,500,000 Cr
1996 F50 GT 1,200,000 Cr

Remember, car club cars do not work for the achievement. You must actually own the car. You can sell it after earning 1 medal though.

Please comment if I missed anything or if I can improve this solution in any way.

You need to earn at least one medal in 14 different Ferrari cars. Press up on the D-pad to see the requirements for the medals.

Beware, although some cars are free to download, they still need to be purchased in game with either in-game credits or real money (MS Points), but that is the case for every car.

Unicorn cars
I do not include "unicorn" cars as free as you need to earn them and they are extremely rare, so most gamers will not have access to them.

Barn discovery cars
Barn discovery cars are available in the main game, but you have to progress through the story and multiplayer, to have them appearing on your map. Then you have to find them in the barn (wrecked). You have to wait until they are fixed before you can use them. There are 9 Barn discovery cars.
* 1964 Aston Martin DB5
* 1958 Aston Martin DBR1
* 1981 BMW M1
* 1992 Bugatti EB110 SS
* 1957 Ferrari 250 Testa Rossa
* 1956 Jaguar D-Type
* 1954 Mercedes 300SL Gullwing Coupe
* 1971 Plymouth Cuda 426 HEMI
* 1965 Shelby Cobra Daytona Coupe

Loyalty cars
To get your loyalty cars you need at least a save file from either FM3 or FM4. Depending on your level, you get those cars:
* 2011 MINI Cooper S (Level 1)
* 2011 Citroen DS3 Racing (Level 5)
* 2012 Dodge Charger SRT8 (Level 10)
* 1969 Chevrolet Camaro SS (Level 15)
* 2008 BMW M3 E92 (Level 20)
* 2012 Jaguar XKR-S (Level 30)
* 2009 Gumpert Apollo S (Level 40)
* 2012 Lamborghini Aventador LP700-4 (Level 50)

Forza Rewards Program
https://rewards.forzamotorsport.net/
Depending on your tier, you get rewards monthly. Redeem them on the site and they will be deliverer in your game within 4 hours. The rewards can be money, cars, tokens,...


Available DLC Packs
* October Car Pack (1957 Chevrolet Bel Air - FREE)
* November Bondurant Car pack (2012 Jeep Wrangler Rubicon - FREE)
* Season pass (2006 Lamborghini Miura Concepts - FREE)
* December IGN Car Pack (1971 AMC Javelin AMX - FREE)
* Rally expansion pack NOT FREE - NO FREE CARS
* January Recaro Car Pack (1995 Ford Mustang Cobra R - FREE)
* Honda Challenge Car Pack - FREE pack, includes 3 free Honda Cars (2013 Civic Si Coupe - 1986 Honda Civic Si - 2013 Honda HDP Fit - FREE)
* February Jalopnik Car Pack (1966 Ford Country Squire - FREE)
* March Meguiar's Car Pack (1998 Nissan R390 - FREE)
* April TopGear Car Pack (2002 BMW M3 GTR - FREE)

Complete List
* 1957 Ferrari 250 California (main game)
* 1957 Ferrari 250 Testa Rossa (Barn discovery - main game)
* 1962 Ferrari 250 GTO (main game)
* 1984 Ferrari GTO (main game)
* 1987 Ferrari F40 (main game)
* 1989 Ferrari F40 Competizione (main game)
* 1991 Ferrari 512 TR (DLC)
* 1995 Ferrari F50 (main game)
* 1995 Ferrari F355 Challenge (main game)
* 1996 Ferrari F50 GT (main game)
* 2002 Ferrari Enzo (main game)
* 2003 Ferrari Challenge Stradale (DLC)
* 2005 Ferrari FXX (main game)
* 2009 Ferrari California (main game)
* 2007 Ferrari Scuderia (main game)
* 2009 Ferrari 458 Italia (DLC)
* 2010 Ferrari 599XX (main game)
* 2011 Ferrari 458 Spider (main game)
* 2011 Ferrari FF (main game)
* 2012 Ferrari 599XX Evoluzione (DLC)
* 2012 Ferrari F12 berlinetta (DLC)

Summary: 15 cars (main game) + 1 Barn discovery (main game) + 5 cars (non free DLC)