the next update of the plugin will also have the ability to add “tags” to each menu item. the slug of each tag will then be added as css class name to the surrounding article html element of each item which you can then use to mark products as needed . perhaps with some css like (assuming a tag of “special offer”)

.special-offer:after {
    content: 'special offer';
    position: absolute;
    top: 0;
    left: 15px;
    z-index: 10;
    background-color: #EFEFEF;
    text-align: center;
    font-size: 90%;
    line-height: 20px;
    display: block;
    padding: 2px 30px;
    -webkit-transform: translateY(-20px) translateX(-60px) rotate(-30deg);
    -moz-transform: translateY(-20px) translateX(-60px) rotate(-30deg);
    -ms-transform: translateY(-20px) translateX(-60px) rotate(-30deg);
    -o-transform: translateY(-20px) translateX(-60px) rotate(-30deg);
    transform: translateY(-20px) translateX(-60px) rotate(-30deg);
    -webkit-transform-origin: top right;
    -moz-transform-origin: top right;
    -ms-transform-origin: top right;
    -o-transform-origin: top right;
    transform-origin: top right;
}