I posted this over in /r/BudgetAudiophile, but would also like to get a second opinion for some recommendations for an amp to power some small/medium passive bookshelf speakers (Aiwa SX-N330).
The budget that I have to work with is about $50 USD ($75 AUD), although I'm not sure whether that's far too little for even an amplifier.
In terms of how I'll be using it, I'll most likely plug it into the TV/Computer/Phone, moving the amp/speakers as needed, and it'll mostly be used for music, with the odd game/movie thrown in. (I don't believe music taste should matter too much for an amp, but it'll probably end up playing video game soundtracks, or other more orchestra-heavy music). Because it's not going anywhere fast, I'd ideally not have to deal with worrying about internal batteries going bad.
As a result, I'd ideally want a 3.5mm jack, but USB/RCA is fine (although the former is preferred over the latter, since I lack a 3.5mm -> RCA cable.)
Although the list is hardly exhaustive, I did take a look around at some of the options that seemed to be within my budget, in a few places (namely /r/BudgetAudiophile). (all prices in USD unless otherwise indicated)
This Nobsound amplifier, which is just over my budget at $56 AUD.
The Dayton Audio GS2.1, which is $49.98, due to a sale.
Nobsound Douk Audio, for $49.99 (this, and the next two are from this thread)
Pyle PDA20BT, for $49.44
Fosi Audio BT-10A-S, which is $49.99
Lepai LP-2020TI, for $34.98
Lepai LP-168HA, which is $42.18 with a power supply, $39.99, without.
Other than that, based on some of the other places, most of the other given options are somewhat outside of budget.