CODE:
var connection = crmConnection.Parse("Url=**** ; Username=***; Password=***");
int indexuom = this.uomlist.SelectedIndex;
int indexpricelevel = this.pricelevellist.SelectedIndex;
int indexproduct = this.productlist.SelectedIndex;
int indexqsc = this.DropDownListqsc.SelectedIndex;
int indexpmc = this.DropDownListpmc.SelectedIndex;
using (var context = new XrmServiceContext(connection))
{
Entity _Item = new Entity();
_Item.LogicalName = "productpricelevel";
_Item.Attributes.Add("pricelevelid", new EntityReference("pricelevelid", new Guid(pricelevelidlist[indexpricelevel])));
_Item.Attributes.Add("productid", new EntityReference("productid", new Guid(productidlist[indexproduct])));
_Item.Attributes.Add("uomid", new EntityReference("uomid", new Guid(uomidlist[indexuom])));
_Item.Attributes.Add("quantitysellingcode", new OptionSetValue(indexqsc));
_Item.Attributes.Add("pricingmethodcode", new OptionSetValue(indexpmc));
_Item.Attributes.Add("amount",new Money(30.0M))
context.AddObject(_Item);
context.SaveChanges();
}