Anyone know of a javascript that can get the values of the id's from the selected options and add them to the inputbox?

For instance, if you select "Product 3" and "Service 2", the inputbox will display $1699.99

HTML Code:
<form action="">

    <ul style="list-style:none;padding-left:0;">
        <select class="products1" name="Products">
          <option id="$100.00" value="Product 1">Product 1</option>
          <option id="$150.00" value="Product 2">Product 2</option>
          <option id="$199.99" value="Product 3">Product 3</option>
        <select class="services1" name="Services">
          <option id="$500.00" value="Service 1">Service 1</option>
          <option id="$1500.00" value="Service 2">Service 2</option>
          <option id="$2000.00" value="Service 3">Service 3</option>
    Total: <input class="totalPrice" type="text" disabled="disabled" value="0.00" />