Steam Market Sales Total at https://steamcommunity.com/market/

smst.js

var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://steamcommunity.com/market/myhistory/render/?query=&start=0&count=1', false);
xhr.send();
if (xhr.status != 200) {
    alert(xhr.status + ': ' + xhr.statusText);
    throw new Error();
}
var totalCount = JSON.parse(xhr.responseText)['total_count'];
xhr.open('GET', 'https://steamcommunity.com/market/myhistory/render/?query=&start=0&count=' + totalCount, false);
xhr.send();
if (xhr.status != 200) {
    alert(xhr.status + ': ' + xhr.statusText);
    throw new Error();
}
var el = document.createElement('div');
el.innerHTML = JSON.parse(xhr.responseText)['results_html'];
var sum = 0.0;
var list = [].slice.call(el.querySelectorAll('.market_recent_listing_row'));
list = list.filter(function (item) {
    return item.children[3].children.length > 1 && item.children[3].children[1].innerText.trim().startsWith('Покупатель');
});
list.forEach(function (item, i, arr) {
    sum += parseFloat(item.children[2].innerText.replace(/,/, '.'));
});
alert('Вы заработали на продаже карточек в Steam: ' + sum.toFixed(2));