Phineas Character

Phineas is available for purchase by two ways

He is sold in the Phineas and Ferb Toy Box Set and as a seperate figure

Here are some links that allow you to buy him

http://www.amazon.com/Disney-INFINITY-Phineas-Not-Machine-Specific/dp/B00HC6A8T8/ref=sr_1_1?ie=UTF8&qid=1458425691&sr=8-1&keywords=disney+infinity+phineas

http://www.amazon.com/Disney-INFINITY-Phineas-Not-Machine-Specific/dp/B00HC6A942/ref=sr_1_2?ie=UTF8&qid=1458425691&sr=8-2&keywords=disney+infinity+phineas

http://www.walmart.com/ip/Disney-Infinity-Phineas-Ferb-Toy-Box-Set/33858964

http://www.walmart.com/ip/Taketwo-Interactive-1117230000000-Infinity-Figure-Phineas/41485562

http://www.toysrus.com/product/index.jsp?productId=30181916&cp=&parentPage=search

Is playable in:

Toy Box

Toy Box 2.0

Toy Box 3.0

Escape from the Kyln

Assault on Asgard

Stitch's Tropical Rescue

Brave Forest Seige

Toy Box Speedway

Toy Box Takeover

Here is a cool video with gameplay of Phineas:

Phineas is one of the most creative and amazing characters in Disney Infinity. In the toy box, he can use his creative mind to build any world you desire whether it's a race track or a castle, Phineas can handle the job. But that is not all he can do. Phineas also has amazing attacks that can defeat any enemies that stand in his way. He can do a cool arm bash that can either destroy an enemy or move them back so he can shoot his baseball gun to destroy them. His baseball gun shoots a baseball that follows the enemy making a great long ranged attack. Phineas is probably one of the best combinations of creativity and attacks and that just makes him one of the best characters ever. 

Here is a link with the full skill tree

https://infinity.disney.com/characters/phineas

Have a amazing day!