[SerializableAttribute()] 
public class SaveMethodComboCollection : System.Collections.ObjectModel.Collection<SaveMethodCombo> 

class MyPage : System.Web.UI.Page
{
    public SaveMethodComboCollection SaveMethodCombos()
    {
        if (HttpContext.Current.Items["Ecom.SaveMethodCombos"] == null)
        {
            SaveMethodComboCollection tempCol = new SaveMethodComboCollection();
            tempCol.LoadCombos();
            HttpContext.Current.Items["Ecom.SaveMethodCombos"] = tempCol;
        }
        return (SaveMethodComboCollection)HttpContext.Current.Items["Ecom.SaveMethodCombos"];
    }
}