gform_sections_accordion.css

.m_collapse_text, .show_collapse .m_expand_text, .m_section{
    display: none; 
}
.show_collapse .m_collapse_text {
    display: inline; 
}

gform_sections_accordion.js

jQuery( function($) {

    var section = [];
    
    var new_div;
    // go through all the Gravity Forms fields
    $('.gfield').each( function() {
        // if the field is a section create a new array for fields and a new container to append the fields
        if ( $(this).hasClass('gsection') ) {
            if ( section.length > 0 ) {
                section = [];
            }
            new_div = $('<div class="m_section"></div>');
            new_div.insertAfter($(this));
        } else {
            // check if the field is the the kind you want to use for the accordion 
            if ( $(this).hasClass('gfield_price') ) {
                // if it's the first element add a custom text to the section name 
                if ( section.length == 0 ) {
                    $(this).prevAll(".gsection:first").find('.gsection_title').append(' <span class="m_expand"><span class="m_expand_text">+ EXPAND</span><span class="m_collapse_text">- COLLAPSE</span></span>');
                }
                // add the field to the section array for reference
                section.push($(this));
                // move the field in the container for the section 
                if ( new_div ) {
                    new_div.append($(this));
                }
            }
        }
    });

    // add the section click behavior
    $('.gsection').click(function(e) {
        e.preventDefault();
        // hide all sections
        $('.m_section').hide().removeClass('show_collapse');
        // if the section content is already visible just hide it ( toggle )
        if ( $(this).next().is(':visible') ) {
            return;
        }
        // show the content in the .m_section
        $(this).next().show();
        $(this).next().addClass('show_collapse');
    });

    // hide all section containers on first run, can be replaced by a css rule
    $('.m_section').hide();
});