Best Buy has Xbox Live 3 month Gold cards (though they're backordered) and 3 month online codes discounted from $24.99 to $14.99.
http://www.bestbuy.com/site/olstemplatemapper.jsp?_dyncharset=ISO-8859-1&id=pcat17071&type=page&ks=960&st=1272086%2C+1419569&sc=Global&cp=1&sp=&qp=crootcategoryid%23%23-1%23%23-1~~q313237323038362c2031343139353639~~ncabcat0700000%23%231%23%232&list=y&usc=All+Categories&nrp=15&iht=n
http://www.bestbuy.com/site/olstemplatemapper.jsp?_dyncharset=ISO-8859-1&id=pcat17071&type=page&ks=960&st=1272086%2C+1419569&sc=Global&cp=1&sp=&qp=crootcategoryid%23%23-1%23%23-1~~q313237323038362c2031343139353639~~ncabcat0700000%23%231%23%232&list=y&usc=All+Categories&nrp=15&iht=n