Well, if you want to look at a Cisco 877 on ebay then second-hand they can be had for under 100GBP, and it work's for me.
I have a 877 connected to BE with a Noise Margin of 0.5 dB DownSteam, Attenuation 40.5 dB, Output Power 19.0 dBm which currently gives me a line sync at 12222 kbps, with no issues.
On a good day I might hit a Noise Margin of 3.0 dB both up and down, but this rare.
Upsteam a bit better with 3.0 dB and but sync at 1308 kbps (Annex A connection).
Testing this on
www.speedtest.net shows - 15ms ping, 10.32Mbps down and 1.07Mbps Up, which I think is pretty darn good given the lines we have in our village.
Can't say you'll get 'N' WiFi or USB connections out of a 877 but with 4.0.018 DSL firmware and IOS 15.0(1)XA; it's proved to be rock solid.
However, the same router was in use when I had BT Business as my ISP, and best I ever got then was a 6Mbps connection.