The price list field on a CRM quote is a "lookup field".   There is special syntax required to retrieve data from a lookup field.

 

Code tested with CRM 2011:

 

var pricelist = Xrm.Page.getAttribute("pricelevelid").getValue();
var pricelistvalue = pricelist[0].name;

 

If you want to see it in a message box, add:

 

alert(pricelistvalue);