understand this sivarap.
you have a
256 Kbps - Kilo bits per second
and bits/8 = byte. so 256/8 = 32.
you can get maximum of
32 KBps = Kilo Bytes per second
small b = bits. capital B = byte.
on the topic, how much you receive depends on the server or wherever you are downloading from. if its a HTTP/FTP server then you can get 30-32 easily, because most are fast these days. if not try using a download manager like Flashget or DAP.
if you are talking about torrents, the golden rule of torrents is your download speed is proportional to your upload speed. so when i was using 256 kbps, to get the max download speed, i had a global upload maximum of 5 KBps. i used to get ~30 KBps i suppose. torrent speeds fluctuate a lot, so you cant expect constant 30 KBps.
EDIT:
@debsuvra
damn
you got first by seconds