Thanks Ravi,

After updating the plugin the (publish-post) page crashed, but i was eventually able to isolate the problem to the code you sent before. I think the code is not compatible with the latest pay per post update.

 /**
 * Enable BuddyBlog dropdown submission type.
 */
add_action( 'bblpro_form_after_form_fields', function ( $form_id, $post ) {

        if ( ! bblpro_ppp_is_form_pay_per_post_enabled( $form_id ) || $post->post_status == 'published' ) {
                return;
        }
    $submission_type = get_post_meta( $post->ID, '_bblpro_submission_type', true );

        ?>
    <div class="bbl-form-field-container bbl-form-field-type-submission-type-container">
        <div class="bbl-form-field bbl-form-field-select">
            <label for="bbl_custom_field"
                   class="bbl-field-label bbl-field-label-type-select"><?php esc_html_e( 'Submission Type', 'sb-buddyblog-custom' ); ?></label>
            <select name="bblpro-post-submission-type" id="bblpro-tax-selectbox-submission-type" class="postform">
                <option value="free" <?php selected( $submission_type, 'free' ) ?>><?php esc_html_e( 'Free Post' ); ?></option>
                <option value="sponsored" <?php selected( $submission_type, 'sponsored' ) ?>><?php esc_html_e( '30 Days | Sponsored Post - ₦50,000' ); ?></option>
            </select>
        </div>
    </div>
        <?php
}, 10, 2 );

add_action( 'bblpro_post_submitted', function ( $post_id, $form_id, $post_data ) {

        if ( ! bblpro_ppp_is_form_pay_per_post_enabled( $form_id ) ) {
                return;
        }

        if ( isset( $_POST['bblpro-post-submission-type'] ) && 'free' == $_POST['bblpro-post-submission-type'] ) {
                update_post_meta( $post_id, '_bblpro_submission_type', sanitize_text_field( $_POST['bblpro-post-submission-type'] ) );
                add_filter( 'bblpro_ppp_skip_post_purchase', '__return_true' );
        }

}, 9, 3 ); 

Thank you for the feedback i’m really grateful for the effort you are giving