The following code will override the default condition fields (New/Used) and will add 10 different options to the condition dropdown:

function ibid_override_simple_auction_condition_fields($auctions) {
  return array(
    'new' => __('Brand New', 'ibid'), 
    'used' => __('1/10', 'ibid'),
    '2/10'=> __('2/10', 'ibid'), 
    '3/10'=> __('3/10', 'ibid'), 
    '4/10'=> __('4/10', 'ibid'), 
    '5/10'=> __('2/10', 'ibid'), 
    '6/10'=> __('6/10', 'ibid'), 
    '7/10'=> __('7/10', 'ibid'), 
    '8/10'=> __('8/10', 'ibid'), 
    '9/10'=> __('9/10', 'ibid'), 
    '10/10'=> __('10/10', 'ibid')
  );
}

add_filter('simple_auction_item_condition','ibid_override_simple_auction_condition_fields');

Note: This tutorial only works with the WooCommerce Simple Auctions plugin + the iBid Auctions theme.