PHP - Duda de Novato

<label for="lprecioyo" class="col-md-1 control-label">L.Precio</label>

	<div class="col-md-2">

		<input type="text" class="form-control input-sm" id="lprecio" placeholder="Lista Precio" readonly>

	</div>

		<?php

			$FiltroLP="lprecio";

			$_SESSION['listaprecio']=$FiltroLP;

		?>

<form class="form-horizontal" role="form" id="datos_factura">

	<div class="form-group row">

	  <label for="nombre_cliente" class="col-md-1 control-label">Cliente</label>

	  <div class="col-md-3">

		  <input type="text" class="form-control input-sm" id="nombre_cliente" placeholder="Selecciona un cliente" required>

		  <input id="id_cliente" type='hidden'>

	  </div>

	  <label for="lprecioyo" class="col-md-1 control-label">L.Precio</label>

		<div class="col-md-2">

			<input type="text" class="form-control input-sm" id="lprecio" placeholder="Lista Precio" readonly>

		</div>

			<?php

				$FiltroLP=1; //Es aqui donde debo poner el valor segun la lista de precio el cliente... por defecto deje el 1.

				$_SESSION['listaprecio']=$FiltroLP;

			?>

	 <label for="rut" class="col-md-1 control-label">R.U.T.</label>

		<div class="col-md-3">

			<input type="text" class="form-control input-sm" id="rut" placeholder="R.U.T." readonly>

		</div>

	 </div>

		<div class="form-group row">

			<label for="vendedor" class="col-md-1 control-label">Vendedor</label>

			<?php

				$sql_vendedor=mysqli_query($con,"select * from users where user_id = '" . $_SESSION['user_id'] . "'");

				while ($rw=mysqli_fetch_array($sql_vendedor))

				{

					$nombre_vendedor=$rw["firstname"]." ".$rw["lastname"];

				}

			?>

			<div class="col-md-3">

				<input type="text" class="form-control input-sm" id="nombre_vendedor" value="<?php echo $nombre_vendedor;?>" readonly>

			</div>

			<label for="fecha" class="col-md-1 control-label">Fecha</label>

			<div class="col-md-2">

				<input type="text" class="form-control input-sm" id="fecha" value="<?php echo date("d/m/Y");?>" readonly>

			</div>

			<label for="email" class="col-md-1 control-label">Pago</label>

			<div class="col-md-3">

				<select class='form-control input-sm' id="condiciones">

					<option value="1">Efectivo</option>

					<option value="2">Crédito</option>

				</select>

			</div>

		</div>

	<div class="col-md-10">

		<div class="pull-right">

			<button type="button" class="btn btn-default" id="menu" data-toggle="modal" data-target="#myModal">

			<span class="glyphicon glyphicon-search"></span> Agregar Productos

			</button>

			<button type="submit" class="btn btn-default">

			<span class="glyphicon glyphicon-save"></span> Grabar Nota de Venta

			</button>

		</div>

	</div>

</form>