Changing the (regular and sale) price decoration and color in Flatsome is pretty easy with a little bit of CSS. Sadly, there's no admin function for this so jump into the Custom CSS section in Theme Options and let's play with some styles!

The price and sale price text have their own aptly named CSS classes:

.price
.price del
.price ins

The ‘del', meaning delete or deleted, is being used here for the crossed out regular price when there's a sale, and ‘ins' is used for the ‘sale' amount. And .price controls the regular text that shows up (and the sale price if you don't want to overwrite ‘ins').

The default color is pure black: #000000. So, to change the price colors you can add something like the following to your Custom CSS:

The same idea applies to style the price text: