CookieClickerAuto.user.js

// ==UserScript==
// @name         Cookie Clicker auto buying script
// @version      0.1
// @description  this scrip will calculate what the best building to buy is, and then buy it. it also buys your upgrades and clicks golden cookies.
// @author       Triktron
// @match        https://orteil.dashnet.org/cookieclicker/
// @grant        none
// ==/UserScript==

function IsReady() {
    if (Game && Game.ready == 1) startAutoBuy(); else setTimeout(IsReady, 200);
}

IsReady();

function startAutoBuy() {
    Game.Notify("Auto buy", "Starting...");

    var autoBuy = setInterval(function test(){
        var note = Game.Notes.find(n => n.title == "Auto buy");
        if (!note) {clearInterval(autoBuy); return;}

        if (Game.UpgradesInStore[0] && Game.UpgradesInStore[0].getPrice() < Game.cookies) Game.UpgradesInStore[0].buy();

        var buildings = Game.ObjectsById.map(building => ({id: building.id, price: building.getPrice(), cps: building.cps(building)}));
        var best = Game.ObjectsById[buildings.sort(function(a,b){return a.price*(a.cps+Game.unbuffedCps)/a.cps-b.price*(b.cps+Game.unbuffedCps)/b.cps})[0].id];
        if (best.price < Game.cookies) {best.buy();note.desc = "just bought " + best.name;} else note.desc = "saving up for the " + best.name + " and need " + Beautify(best.price - Game.cookies) +  " to buy it";
        note.life = 999;
        Game.UpdateNotes()

        Game.shimmers.forEach(function(shimmer){if(shimmer.type == "golden" && shimmer.wrath == 0){shimmer.pop()}})
    }, 500);
}

i don't know why i made this.... i just... felt like making it... XD feel free to try it out!