Both come unlocked and feature GSM/LTE support, so you'll be able to use them on carriers like AT&T, T-Mobile, Straight Talk, MetroPCS, Cricket Wireless, and a few others.
The cheaper of the two, Sony Xperia XA is available for just $179.99, which means you'll be saving 28% off the phone's $249.99 suggested retail price. The phone is available in four colors: Black, White, Lime Gold, and Rose Gold.
If you decide to go for the Sony Xperia XA Ultra, you'll be saving much less. The smartphone can be had for $269.99, 18% discount off the full price ($329.99). Customers can choose from three available colors: Black, White, and Lime Gold.
Amazon throws in free shipping, and if you have Amazon Prime you'll be getting it as early as April 6, but only if you order within the next 20 hours or so. As the title says, each of these phones come with US warranty, so you won't have to pay extra in case it needs repairing.