There's still loads of classic Amiga goodies to be had for not a lot.
Amiga 500s you can get very cheap. I just bought an A600 for £20. I've bought a 68030 accelerator for the A1200 for £50, and then bought another for £60 shortly after.
You just need to watch eBay carefully, that's all. The 600 went at a funny time of day, so was cheap. The A1200 accelerators - one of them had a capacitor come off (5 seconds with a soldering iron fixed that), and the other one was advertised as a "ROM upgrade" despite the fact it was clearly an accelerator.
Point is, if you go to the established sellers you're going to pay a lot more. If you look around and be patient, you will find a bargain. Heck, the thing I've been playing with most was a bridgeboard that someone sent to me for the price of postage, can't get much better than that.
Remember - just because some people have put a high price tag on an Amiga thing, doesn't mean they'll actually get that price....