<a href="#" class="buybtn"> <span class="buybtn-text"> купить </span> <span class="buybtn-hidden-text"> 50руб </span> <span class="buybtn-image"> <span></span> </span> </a>

.wrap{  
  margin:100px 30%;  
  }  

  a {  
  color: #FFFFFF;  
  text-decoration: none;  
  }  
  .buybtn {  
  -moz-transition: all 0.3s linear 0s;  
  background: -moz-linear-gradient(center top , #FF8400 0%, #FF6600 100%) repeat scroll 0 0 transparent;  
  border: 1px solid #FF5A00;  
  border-radius: 5px 5px 5px 5px;  
  box-shadow: 0 1px 1px rgba(255, 255, 255, 0.8) inset, 1px 1px 3px rgba(0, 0, 0, 0.2);  
  clear: both;  
  display: inline-block;  
  float: left;  
  font-family: Arial,sans-serif;  
  height: 45px;  
  margin: 10px 0;  
  overflow: hidden;  
  padding-left: 20px;  
  padding-right: 65px;  
  position: relative;  
  }  
  .buybtn-text {  
  -moz-transition: all 0.2s linear 0s;  
  color: #6E1D08;  
  display: block;  
  font-size: 18px;  
  padding-top: 10px;  
  text-shadow: 0 1px 1px rgba(255, 255, 255, 0.3);  
  white-space: nowrap;  
  }  
  .buybtn-hidden-text {  
  -moz-transition: width 0.3s linear 0s;  
  background: none repeat scroll 0 0 #6E1D08;  
  box-shadow: -1px 0 1px rgba(255, 255, 255, 0.4), 1px 1px 2px rgba(0, 0, 0, 0.2) inset;  
  color: #FFFFFF;  
  font-size: 18px;  
  height: 100%;  
  line-height: 42px;  
  overflow: hidden;  
  position: absolute;  
  right: 52px;  
  text-align: left;  
  text-indent: 17px;  
  text-shadow: 0 -1px 1px #363F49;  
  text-transform: uppercase;  
  top: 0;  
  white-space: nowrap;  
  width: 0;  
  }  
  .buybtn-image {  
  border-left: 1px solid #FF5A00;  
  box-shadow: 1px 0 1px rgba(255, 255, 255, 0.4) inset;  
  height: 100%;  
  position: absolute;  
  right: 0;  
  top: 0;  
  width: 52px;  
  }  
  .buybtn-image span {  
  -moz-transition: all 0.3s linear 0s;  
  background: url("http://www.nizckod.ru/vsjak/cart.png") no-repeat scroll 75% 55% transparent;  
  height: 38px;  
  left: 50%;  
  margin: -20px 0 0 -20px;  
  opacity: 0.7;  
  position: absolute;  
  top: 50%;  
  width: 38px;  
  }  
  .buybtn:hover .buybtn-text {  
  color: #FFFFFF;  
  text-shadow: 0 1px 1px #5D81AB;  
  }  
  .buybtn:hover .buybtn-hidden-text {  
  width: 100px;  
  }  
  .buybtn:hover .buybtn-image span {  
  opacity: 1;  
  }  
  .buybtn:active {  
  background: none repeat scroll 0 0 #FF5A00;  
  }