Hello,
Go to Pages > edit front page > edit WPBakery custom CSS http://prntscr.com/ss8tb6 > find below code and change the currency symbol
.corpo-price-block h3:before {
content: "$";
font-size: 36px;
vertical-align: top;
font-weight: 500;
position: relative;
top: 5px;
}
Regards