Somewhat confused by your post!
All movers (expensive or otherwise) do much the same thing - come and pack up your stuff, put it into a container, and then put it on a ship. So you may not SEE the "HK sea shipping" but that's how most stuff is moved.
A small amount of light stuff can occassionally go via air - MUCH more expensive.
Post???? Post is HUGELY more expensive again!
How much do you have? Is it, like, a few boxes or an entire household?
For a small number of boxes etc, the cheapest way is to contact removal companies and see if you can get into a "part shipment" - ie your boxes go into somebody else's container who is not quite full and you get to pay only a fraction of the cost. As per most normal removals, will take a few weeks to arrive - you also may have to wait until somebody else is going "your way". You can deal with your own customs - just be careful to read all the documentation and ensure you have nothing dubious in the shipment - usually this means NO FOOD, NO CD's/DVD's, NO VIDEOS etc. (Former is a quarantine risk, latter they check for porn and piracy!).
I'd start looking in the yellow pages for removal firms and then start asking around, they should point you in the right direction.