I was just there a couple of weeks ago.
How much is not epxensive?
Basically you have two choices where to stay. Hong Kong Island or Kowloon, which is accross the bay from Hong Kong.
We stayed in the renaisance which was nice. About €85 a night. You can get cheaper though.
There is a shuttle bus from airport to hotels. Could take about 45 minutes. Taxi's cost about $300 (hong kong dollars), but the bus only costs $120.
However there seems to be a little scam going on. Before you actauly leave the arrivals hall there is a girl who is giving out leaflets offering 25% off the bus journey. So basically it is only $90.
It is very humid and sticky in Hong Kong. However very showery. So best to get an umbrella or if you don't want the hassle, a light jacket.
We were there for 3 days and found it very expensive. However in saying that we spent the 3 weeks before that in Thailand which was ridiculously cheap. Hong Kong seemed dear at the time but in looking back it is about the same as Irish prices.
Not too sure about what to say about shopping. I mean it is perfect if you have the money. Each designer label seems to have there own store. And on top of that each hotel seems to be joined on to a shoping centre.
We went to Stanley Market. It was good bit out but can be done as part of a trip, which brings you to the Peak as well. There is also a night market in Kowloon which is worth a look but has limited stuff. "Shopping" is so broad, so if you have any specific questions post them here.
And if you have any other q's let me know. How long are you going for?