Finally i came out with a solution! The thing was that.. as Mike C. says, the extra code could help to solve the problem. The problem was that the form that i'm trying to submit it's an Ajax.BeginForm of MVC so.. the main problem is the ajax submit of that form, that was the second submit!
I couldn't change that behavior.. only changing the Ajax.Beginform with a Html.Beginform.. thing that i don't want to do. So.. i came out with this "rusty" solution:
$("input.price").live('keypress', function (e) {
if (e.keyCode == 13) {
$(this).attr('data-submitting', true);
}
});
$("input.price").live('change', function (e) {
if (!$(this).attr('data-submitting')) {
$(this).closest('form').submit();
}
});