Besides using the PSP as a portable Amiga emulator I'll chip in a word for "stationary" around 100USD mark system. The Intel Compute stick, yes it's a "tiny" x86 soc that you just plug into your monitor or TV (via HDMI). Then you can use WinUAE that blows away the Android/ARM ports in features and performance and you also score a fully working x86 Windows/Linux machine and can use it as a HTPC etc and open up the door for huge amounts of x86 software. And great for the ones that want a dedicated x86 Amiga emulator machine.
Specs: Intel Atmo Z3735F (4 cores @ 1.33GHz), 2GB ram, 32GB eMMC Storage and a micro SD slot.
Tho limited to one USB port a USB-Hub is nearly a must if not going for a all in one keyboard/mouse combo and you do not need any USB peripherals on top of that.
Soon there will be a new stick out with a faster CPU and 4GB of ram so might be worth waiting for that one.