This userscript removes any listing marked as "Freemium" and "Free*", on alternativeto.net when the site's filter is set to free.

gistfile1.js

// ==UserScript==
// @name         Alternativeto.net ~Free != Free
// @namespace    https://gist.github.com/fisknils
// @version      0.1
// @description  This script removes any listing marked as "Freemium" and "Free*", when the site's filter is set to free.
// @author       Fisknils
// @match        *://alternativeto.net/*?license=free*
// @grant        none
// ==/UserScript==

// This is the configurable part
var removeFreemium = true; // remove items listed as Freemium
var removeFreeish = true; // remove items listed as Free*



// counter
var xDel = 0;

// all listed items on the page
var items = document.getElementsByClassName('item-wrapper');

// loop through
for(var i in items) {
    try {
        // I'm lazy...
        item = items[i];
        ihtml = item.innerHTML;
        
        // if it's innerHTML contains Freemium or Free*, remove this element, and increment the counter
        if((ihtml.indexOf('Freemium') > 0 && removeFreemium) || (ihtml.indexOf('Free*') > 0 && removeFreeish)) {
            item.parentNode.removeChild(item);
            xDel++;
        }
        
    } catch(err) {
        //console.log(err.message);
    }
}

console.log('removed ' + xDel + ' listings due to being "Freemium" or "Free*", while looking for Free');