[рони]

SNEG,
НЕНАДО обращаться к тому чего нет -- либо ставите скрипт после <div id="totalprice"></div>
либо в любое место но после готовности страницы

$(window).load(function ()
{
      var vdscpu = 0;
      var vdsram = 0;
      var vdshdd = 0;
      document.getElementById('totalprice').innerHTML = (vdscpu + vdsram + vdshdd );
      $("#CPUslider").slider({ from: 1, to: 20, step: 1, round: 1, scale: [1, '|', 5, '|' , 10, '|', 15, '|', 20], skin: "round_plastic",
        onstatechange: function( value ){
        vdscpu = +value;
        document.getElementById('totalprice').innerHTML = (vdscpu + vdsram + vdshdd );
        }
      });
      $("#RAMslider").slider({ from: 1, to: 16, step: 1, round: 1, scale: [1, '|', 4, '|' , 8, '|', 12, '|', 16], skin: "round_plastic",
        onstatechange: function( value ){
          vdsram = +value
          document.getElementById('totalprice').innerHTML = (vdscpu + vdsram + vdshdd );
        }
      });
	    $("#HDDslider").slider({ from: 1, to: 100, step: 1, round: 1, scale: [1, '|', 10, '|' , 20, '|', 30, '|', 40, '|', 50, '|', 60, '|', 70, '|', 80, '|', 90, '|', 100], skin: "round_plastic",
        onstatechange: function( value ){
          vdshdd = +value
          document.getElementById('totalprice').innerHTML = (vdscpu + vdsram + vdshdd );
        }
      });
      })