Option 1
window.onload=function(){
setInterval(autoClick,100);
}
function autoClick(){
if(document.getElementsByClassName("free").length>0){
document.getElementsByClassName("free")[0].click();
}
}
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Option 2
function autoClick(){
alert("I am loaded and automatically clicked");
}
window.onload = function(){
document.getElementsByClassName("free")[0].click();
}