If you have only one phone, and dont need QoS, go for Multitech RF550 routers they are working fine and cost around 150-200$
For only one phone, and only one user using this internet access, you probably dont want to invest in a QoS router...unless this user is using 100% of his internet access by himself (torrent downloads, for example).. but for regular usage (email & web) no QoS should be required.
For QoS Kentrox is definitely your best bet.