That price is too high for a stock A600. You can use almost any 2.5 laptop hdd (<4gb . less than 2gb is even better) with an a600 so no hdd is no problem at all. However, he didn't state the kickstart version. if it's not 3.1 or 37.350, it may have problems using the hdd. However that's not a big deal too, you can find compatible roms easily (infact I can provide you 37.350 roms very cheaply).
a600 was most popular in the UK. So you may check UK if you want an a600, they're cheapest there. I saw them going for as low as 20-30$. But shipping would be a problem. This auction also has a shipping price of 50$ so I think buying from a UK auction would be much better.
Also please bear in mind that this is a PAL amiga. You can't use it with your regular NTSC tv or 1084. You need a multisystem tv or a multisync monitor.
