Budget option if the amp has an XLR out is a Behringer MA400. Great bit of kit, a simple XLR + aux input + headphone amp for not much dough.
There are plenty of iOS interfaces like the iRig and Sonic Port, they’l also let you run amp sims and effects on the iDevice too.
The cheap Zoom multis combine everything you would need including amps, fx, tuner, looper etc.
The Bighead beats them all for clean pristine sound quality though, and is capable of driving higher impedance headphones that the iOS and Zoom devices struggle to push enough volume into.