Hi,
When importing these products into the UK, you will need the paperwork to show a value for them regardless if there's insurance or not on the cost of 'shipping' them.
When the units arrive here, either all of some of these - Import Tax, VAT or excise duty will apply. The agents will look at the values given from which to base their calculations.
don't be tempted to deliberately declare a purposely 'low' value - it's one of the oldest tricks in the book and HMRC officials aren't stupid ! they also have access to pricing lists of pretty much anything you can buy to 'check up on pricing' - so don't write the 3K gaming rig as a $250 computer.
If you 'don't' include insurance, and the package goes missing, you won't be able to claim. If you decide to take insurance and write down the value (please don't!) if it goes missing, you'll only be able to claim the amount you wrote it for.
Personal items are subject to the above taxes, regardless if they're new or 2nd hand and there's no such thing in reality as being 'stung' for the taxes as they can be looked up and found out about very easily -
http://customs.hmrc.gov.uk/channelsPortalWebApp/channelsPortalWebApp.portal?_nfpb=true&_pageLabel=pageTravel_ShowContent&id=HMCE_CL_000014&propertyType=document#P28_2966I import quite a bit from the US and more so in the future, so I'd suggest fully insuring your items and calculating the landed costs from the above info. The only 'real' way to reduce that landed cost, is to find a cheaper shipping fee in your case, or, perhaps forgo the monitors and get ones from here.
Cheers, DtM! West London & Slough UK!