function updateGrid() {
  $(".grid_3").each(function(){
    var pp = $(this).find(".latest-offer-price").text();
    var price = Number(pp.substring(1, pp.length));
    var familyPrice = "£" + price * 4;
    $(this).find(".latest-offer-price").text(familyPrice);
   })
 }
$(document).ajaxSuccess(function(){
  setTimeout(updateGrid,30)
});
updateGrid();`

`<div class="grid_3 alpha omega selected">
  <div>
   <p class="latest-type">
     <span class="latest-offer-price">£100</span>
     <span>pp</span>
   </p>
  </div>
</div>`