<!-- language: lang-html -->
<p>£{{plant_price}}</p>

    <div v-if="selected.plant.variations.length > 0 ">
      <select v-model="selected.plant.selected_variation" class="form-control">
        <!-- inline object literal -->
        <option v-for="(variation, i) in selected.plant.variations" :selected="variation.id == selected.plant.selected_variation ? 'selected' : ''":value="variation.id">
          {{variation.name}}
        </option>
      </select>
    </div>

<!-- language: lang-js -->
var app = new Vue({
  el: '#vueApp',
  data: {
    selected: {
      type: {a: '' , b: ''},
      vehicle: '',
      plant: {
      }
    },
  computed: {
plant_price: function() {
  if (this.selected.plant.variations.length > 0 ) {
      var variant = _.find(this.selected.plant.variations, {id: this.selected.plant.selected_variation });
      return variant.price;
  } else {
    return this.selected.plant.price;
  }
}
...

selected:Object
    type:Object
    vehicle: "Truck"
    plant:Object
       id:26
       price:"52"
       regular_price:"100"
       selected_variation:421
       variations:Array[2]
          0:Object
              id:420
              name:"small"
              price:52000
              regular_price:52000
          1:Object
               etc...