Here's a cheap USB GPS receiver which can be used in your laptop with suitable GPS software. It uses an older chipset, SirfStar II, so not as good as the bluetooth GPS receiver on offer at the Orange Accessories store, but it's still very inexpensive.
I'm using them at home for hobby GPS software development, and it's the cheapest way to pickup one of these. Good service from PCWB also.
Note that it says stock available to order, but it is indeed in-stock, as I ordered 3 of them yesterday and they all arrived today, using the £4.99 postage.
Receiver: 12 channel
SBAS: WAAS, EGNOS
Product Description: Globalsat BU-303 - GPS kit
Product Type: GPS kit
Dimensions (WxDxH): 5.9 cm x 4.7 cm x 2.1 cm
Weight: 145 g
Update Rate: 0.1 second