if you get on eBay and do a search for "Speedstream 5660" there are a number of them available. I happen to have that one and it works fine. Not sure how you would go about getting it shipped to England and all, but it's definitely cheaper.
SAR 110 : £82.19
SAR 703 : £58.69
SAR 705 : £82.19
SAR 715 : £105.69
See the spec for what you need. I would say that the main difference between the 715 and the 110 is that the 705 (although harder to configure) supports more features if set-up correctly. MSN Messenger over NAT for example.
The 703 is the basic deal and has a single 10Mbps ethernet port, if you decide to use a hub for connection to other PCs, that's the speed limit.
The 715 (my router) has 4 ethernet ports capable of 10/100Mbps via a built in 10/100Mbps switch and is in essence a 4 port version of the 705.
I strongly recommend it as a decent value for money piece of kit. If however, you won't need more than 1 port, it's either the 703 or 705 IMHO.
You don't have to intermingle network traffic on a bus that was meant for mice and printers. Network traffic (IMHO) should stay on a network bus. But I'm talking from a perspective of an oldtime network junkie. If you're just interested in browsing the web, I guess a USB solution would be fine. You make the call.
<i>It's always the one thing you never suspected.</i>