Replace the $none_string in 'All Products for WooCommerce Subscriptions' with the price and ONE TIME string

custom_one_time_purchase_string.php

<?php

add_filter( 'wcsatt_single_product_one_time_option_description', 'custom_one_time_purchase_string', 12, 2 );
function custom_one_time_purchase_string( $none_string, $product ) {
    // Alter the value of $none_string to use a custom string
    $none_string = "ONE TIME - " . $product->get_price_html();
    return $none_string;
}