A little (and dirty) script to help with $-apocalypse in Unitedgamers steam group.

UnitedGamersHelper.user.js

// ==UserScript==
// @name         UnitedGamers helper
// @namespace    https://greasyfork.org/users/2205
// @version      0.4
// @description  Replaces $ with link to steamgifts
// @author       Ryzhehvost
// @license      Apache-2.0
// @match        https://steamcommunity.com/groups/TwarArenaGiveaways/discussions/*
// @match        https://steamcommunity.com/groups/UG-GA/discussions/*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function FixComments (comments){
        for (let i=comments.length-1; i>=0; i--) {
            let text = comments[i].innerHTML;
            console.log(text);
            let re = /[^\s^>]*[^m](\/giveaway[^\s^<]*)/g;
            text = text.replace(re, '<a class="bb_link" href="https://steamgifts.com$1" target="_blank" rel="noreferrer">https://steamgifts.com$1</a>');
            if (comments[i].innerHTML != text) {
                comments[i].innerHTML = text;
                //add a notice
                let noticeDiv = document.createElement("span");
                noticeDiv.className = "commentthread_workshop_authorbadge";
                noticeDiv.appendChild(document.createTextNode("(fixed link)"));
                comments[i].parentElement.querySelector("div.forum_author_menu").after(noticeDiv);
            }
        }
    }

    function InjectPasteProcessor (editboxes) {
        for (let i=editboxes.length-1; i>=0; i--) {
            editboxes[i].addEventListener('paste', (event) => {
                let paste = (event.clipboardData || window.clipboardData).getData('text');
                let reSG = /https?:\/\/(?:www\.)?steamgifts\.com(\/giveaway[^\s<"]*)/gi
                if (paste.match(reSG)!= null) {
                    paste = paste.replaceAll(reSG, "$$$1");
                    event.target.setRangeText(paste,event.target.selectionStart, event.target.selectionEnd,"end");
                    event.preventDefault();
                }
            });
        }
    }

    let comments = document.getElementsByClassName('commentthread_comment_text');
    FixComments(comments);

    let editboxes = document.getElementsByClassName('commentthread_textarea');
    InjectPasteProcessor(editboxes);

    let replyboxes = document.getElementsByClassName('forumtopic_reply_textarea');
    InjectPasteProcessor(replyboxes);


    let mutationObserver = new MutationObserver(function(mutations) {
        mutations.forEach(function(mutation) {
            mutation.addedNodes.forEach( function(currentValue, currentIndex, listObj) {
                if (currentValue.nodeType == Node.ELEMENT_NODE) {
                    let comments = currentValue.querySelectorAll("div[class^='commentthread_comment_text']");
                    FixComments(comments);
                    let editboxes = currentValue.querySelectorAll("textarea[class^='commentthread_textarea']");
                    InjectPasteProcessor(editboxes);
                    let replyboxes = currentValue.querySelectorAll("textarea[class^='forumtopic_reply_textarea']");
                    InjectPasteProcessor(replyboxes);
                }
            });
        });
    });
    mutationObserver.observe(document.documentElement, {
        childList: true,
        subtree: true
    });

})();