view.rb

<div class="row expense_amount">
  <div class="control-group string required error">
    <label class="string required control-label" for="wallet_expenses_attributes_0_name">
      <abbr title="required"></abbr> Expense name
    </label>
    <div class="controls">
      <input class="string required" id="wallet_expenses_attributes_0_name" name="wallet[expenses_attributes][0][name]" size="50" type="text" value="" />
      <span class="help-inline">is too short (minimum is 3 characters)</span>
    </div>
  </div>
  <div class="control-group currency required">
    <label class="currency required control-label" for="wallet_expenses_attributes_0_amount">
      <abbr title="required"></abbr> Amount
    </label>
    <div class="controls">
      <div class="input-append">
        <input class="currency required" id="wallet_expenses_attributes_0_amount" name="wallet[expenses_attributes][0][amount]" size="30" type="text" value="435435" />
        <span class='add-on'>pln</span>
      </div>
    </div>
  </div>
  <div class="control-group hidden">
    <div class="controls">
      <input class="hidden" id="wallet_expenses_attributes_0_wallet_id" name="wallet[expenses_attributes][0][wallet_id]" type="hidden" />
    </div>
  </div>
</div>