Samplers were cheap? I remember the few I might have been able to acquire from the one or two local shops that had Amiga stuff being at least a hundred bucks - a comparative fortune back when I was on $5 a week pocket money.
Some models were cheaper than that. As an example you can see here[1] this particular model was 30 pounds in 1992, which is equivalent to about 50 dollars[2].
Depending on the time or place they may have been a bit more expensive so it makes sense that in your case you had to spend $100... but let's not forget that a stand-alone sampler was at least 10 times more expensive, so the Amiga was still a way cheaper option than e.g. an Atari ST + MIDI-connected stand-alone sampler.
Also we have to consider that there were sample libraries distributed on floppy - so with an Amiga you could still have "cool sounds" even without a sampler interface - the main point being that audio playback on Amiga was higher quality than most competitors.
Depending on the time or place they may have been a bit more expensive so it makes sense that in your case you had to spend $100... but let's not forget that a stand-alone sampler was at least 10 times more expensive, so the Amiga was still a way cheaper option than e.g. an Atari ST + MIDI-connected stand-alone sampler.
Also we have to consider that there were sample libraries distributed on floppy - so with an Amiga you could still have "cool sounds" even without a sampler interface - the main point being that audio playback on Amiga was higher quality than most competitors.
[1] https://youtu.be/i9MXYZh1jcs?t=184
[2] https://fxtop.com/en/historical-exchange-rates.php?YA=1&C1=G...