I wish the courses page be able to query courses by price ... found this bit, and hoped it would do the work...
content-archive-course.php
$default_order = apply_filters( 'thim_default_order_course_option', array(
    'newly-published' => esc_html__( 'Newly published', 'eduma' ),
    'alphabetical'    => esc_html__( 'Alphabetical', 'eduma' ),
    'most-members'    => esc_html__( 'Most members', 'eduma' ),
    //'price'             => esc_html__( 'Price', 'eduma' )
) );;
Also bit in: learnpress_v3_functions.php
if ( !function_exists( 'thim_course_order_query' ) ) {
    function thim_course_order_query( $query ) {
        if ( !$query->is_main_query() ) {
            return;
        }
        if ( !is_post_type_archive( 'lp_course' ) && !is_tax( 'course_category' ) ) {
            return;
        }
        // Sort
        if ( isset( $_POST['course_orderby'] ) ) {
            switch ( $_POST['course_orderby'] ) {
                case 'alphabetical':
                    $query->set( 'orderby', 'title' );
                    $query->set( 'order', 'ASC' );
                    break;
                case 'most-members':
                    $query->set( 'orderby', 'meta_value_num' );
                    $query->set( 'meta_key', 'thim_real_student_enrolled' );
                    $query->set( 'order', 'DESC' );
                    break;
                case 'price':
                    $query->set( 'orderby', 'price' );
                    $query->set( 'order', 'ASC' );
                default:
                    $query->set( 'orderby', 'date' );
                    $query->set( 'order', 'DESC' );
            }
        }
Any help appreciated.