For 300 ukp, you can pick up a pretty good spec A1200, but not 'high end' by any stretch.
I was lucky, I picked up an A1200 with HDD, 040/33 and 16Mb Ram (now 64mb) and IDE splitter for 20 ukp. It was a bit tatty, but I swapped the upper case for the one on my 030/50 A1200. It even has a 250W PC PSU cobbled on to it. It's not pretty, but it works. Unfortunately my Mouse has shed it's mortal coil, and I can no longer use my either of my Miggys! A Serial mouse adapter is on it's way...
Still, you can always emulate... I know WinUAE is free (Toni W
!!), but legal Roms aren't. Amiga Forever 6 now comes with virtually every Rom and Workbench up to and including OS 3.9, as well as a PPaint 7.1, loads of preset configurations plus a few utils and games etc. At least you get *real* hi res, fast Workbench screens under P96, access to big HDDs and lots of Ram. For 50 ukp. Cloanto should be applauded for sticking with the Amiga in any form, and AF6 will probably run more games than any one REAL Amiga. (Please Akira... don't beat me up on this! Please?
300 ukp won't buy a top end Amiga, although I wish it would
. As you say, a lower end machine is more compatible than an 060 zorro'd, Picasso 4 A1200 tower with all the bells and whistles... AF6 can emulate just about any real Amiga except PPC). Any budget PC will run AF6 at faster speeds than many real Amiga's.
IMHO an A1200, 030/50 or 040, 32mb Ram, 1GB Hdd, high density floppy, scandoubler and 17" pc monitor... should do for most things. Or Emulate.
(running for cover... did Akira see me?)