<button type="submit" class="btn btn-default">
                    <i class="fa fa-shopping-cart"></i> Buy Now
                </button>

<span><i class="fas fa-shopping-cart glyph"></i></span>
<input type="button" class="button" value="Basket" />

.glyph{
    position: relative;
    left: 35px;
    pointer-events: none; //this makes the glyph clickable as part of the input
}

.button{
    width: 100px;
    height: 100px;
    padding-left: 20px;
}