my mum bought me mine from Spotlight. $40 normal standard price i thnk. she got it on special for about $10. love it. perfect amount of pockets but there arent any fiddly zips n stuff on the inside. it has one of those bottle keep-warm bag things in it too. its an adjustable over the shoulder strap and also has backpack straps so you can convert it. comes with a change mat aswell. its deceiveingly big on the inside. can fit easily in it...
box of scented nappy dry bags
packet of wipes
an assortment of first aid/baby aid bits n pieces (bandaids, thermometer, small tube of bepanthen and sample size of sudocream amng other things)
in one pocket about 4 sposies or one cloth (outer, hemp liner + booster)
in the rest of the bag, the bottle bag thing, a tupperware container of formula, a spare scoop, 2 changes of clothes (warm and cool) a huge tube of sunscreen, couple of travel packets of tissues, 2 wraps, bibs, wallet, keys, phone, some shopping

hehe and still fits under the pram (albeit i have a huge shopping trolley lol) but my DP also has no qualms about carrying it, in fact he normally grabs it for me. its a bright light blue (iygwim) with a navy stripe. my friend has the black one with a white stripe? (i know its black, not sure about the stripe colour lol) and the backpack straps are padded.
and showing no signs of wear and tear
if you want a pic i can pm you one.... but if you are looking for cheap i wouldnt walk past it.