Got mine for around $35, very easy set up, just plug your router into the modem, run a cat 5 cable from the outputs on router to each computer, and install the software.
The wireless are a bit more expensive and unless you have laptops or a situation where running wire is difficult you really dont need wireless.
Also the wireless have different speeds of data transfer, be sure to take this into account. Wireless G with a high rate of transfer would be the best.
More info on wireless here
Wireless routers are not as secure as hard wired....
http://www.firewallguide.com/wireless.htm Wireless Broadband Routers for Home
The newest generation of wireless routers for home broadband networks use a technology called 802.11g. An 802.11g wireless router supports more bandwidth than their older 802.11b counterparts. That lets you add more computers to a network without bogging it down. You'll also notice faster file sharing and printing. As with all network gear, consider the cost, features, and brand name when choosing your wireless broadband router. Individual preferences ultimately make this a personal decision.
http://compnetworking.about.com/cs/wirelessrouters/tp/80211ghome.htmFrequenty Asked Questions (FAQs) in Wireless Networking
http://compnetworking.about.com/od/wirelessfaqs/