While it might seem that there is plenty of useful hardware in the item you purchased you might struggle for an awful long time trying to find a use for some or all of the items. While consumer items are made up of transistors, transformers, ICs, LEDs, resistors, capacitors, etc, etc, the specific components may or may not be common to something you'd want to construct. You are probably correct in assuming that it has an audio amplifier or two that might be useful in something else. The problem - does the amp actually work or could that be why you found it in the thrift store. That might take some time to figure out and then more time finding ways to modify it to suit your needs.
What I do with stuff like this - strip out the things that I might find generally useful - power cords, switches and common items like that. Next I try to extract large capacitors - and power transformers being sure that I identify the primary and secondary leads before clipping the wires. The smaller components - if I can see what they are AND I know I can remove them in the future I might toss the board in a pile with similar boards. Maybe I'll pirate a component or two at some point. When the pile gets large I simply start tossing stuff. As with all "used" electronics you might want to be sure you can eventually test what you are re-using so that you don't waste a lot of time when you build something - wondering if the components are good or if you made a wiring or design mistake. It's one thing if you are a seasoned pro and can recognize likely mistakes. In my own case, I don't need to add confusion so I try to start with new (though maybe low cost) stuff.
If it's an amp that you want you might find enough stuff for a DC power supply in your machine that you can salvage. Then think thru the construction of an audio amp - if that's what you need. There are a number of audio amp ICs that are fairly simple to use and their data sheets contain schematics - or you can find them here. That way you start with some known good design, you know more about inputs and outputs, etc. In my opinion this greatly increases your chances of success.