These are the 2 mobile platforms that I use to buy Bitcoin and a few alt coins.
Cash App Link:
Try Cash App using my code and we’ll each get both $5! BDSHVNX
Coinbase lets you conveniently and securely store, and trade digital currencies like bitcoin and ethereum. http://goo.gl/cb5NZe (get $10 buying $100 or more Bitcoin with this referral)