tsibiski

Here was my solution, for anyone else who comes along with the same question. I put this in my theme’s functions.php.

This is working well. It prevents discounts being applied to products under my specified price.

add_filter(
    'pms_woo_get_discounted_price',
    'my_disable_member_discount_under_500',
    10,
    5
);

function my_disable_member_discount_under_500(
$discounted_price,
$base_price,
$product_id,
$member_id,
$product
) {
if ( empty( $product ) || ! is_object( $product ) ) {
    return $discounted_price;
}

/*
 * Categories that should enforce
 * the minimum-price membership rule
 */
$restricted_categories = array(
    'my-category',
    // 'another-category',
    // 'another-category-2',
);

/*
 * Check whether product belongs
 * to one of the restricted categories
 */
$has_restricted_category = false;

foreach ( $restricted_categories as $category_slug ) {

    if ( has_term( $category_slug, 'product_cat', $product_id ) ) {
        $has_restricted_category = true;
        break;
    }
}

/*
 * If product is NOT in a restricted category,
 * allow normal discounts
 */
if ( ! $has_restricted_category ) {
    return $discounted_price;
}

/*
 * Apply minimum price rule
 */
$original_price = (float) $base_price;

if ( $original_price < 500 ) {
    return null;
}

return $discounted_price;
}