Search the thread for Hong Kong.
I got the CSL SIM for about $10 USD and it included all the data I used in a week.
Now I'm not sure if there was a limit/cap or I just didn't use enough of it to hit a cap. I used it in the hotel instead of paying for hotel wifi IIRC.
I bought a Huawei E585 off eBay for about $110, from a Hong Kong seller incidentally. Took about 2-3 weeks to arrive.