Cost of airfreight is very expensive as volume not weight is used to cost it. Also, as fuel prices increase, so too to the cost of freight as well.
Biggest rip off is import, custom and VAT added to anything bought outside the EU. Dont forget to thank the good old Royal Mail either. They levy a nice charge for 'paying the vat' on your behalf (for which you have no option to accept).
Having said that, I've bought stuff from HK and saved pounds. It does seem though that as HK (and other Far East suppliers) have become more popular, they have jacked up their price to the customer so, although the difference is now margin, it is still there. Just.
For example, helicopter fuselages from one well know Far East supplier were often £100 cheaper after being imported compared to buying direct in the UK. Now, the difference is as little as £25 and sometimes, they actually cost more.