This is a long answer to what should be an easy question, but it's complex. So NC is an ABC state and SC is not.
In NC it depends upon which ABC board you are in as to what they have ordered and have in stock.
In general Bourbons which aren't highly sough after are less expensive in SC, but each store is independent. Scotch tends to be less expensive in NC, especially when it goes on sale. If the bottle is highly sought after then it's typically less expensive in NC, but likely very difficult to find.
Sales in NC are announced ahead of time and run for a month. Every ABC in the state will have the same price on a sale item. Now we recently allowed discount sales so if an ABC board decides to do so they can discount the extra bottles to get them sold. I recently go $75 bottles of scotch for $30, which is lower than I had EVER seen that bottle in more than 15 years. Discounted bottles are typically not announced and some ABC boards mark them as being on sale, while others just mark them down and you have to figure out if they are discounted or not.
In NC we have 168 ABC boards and 432 ABC stores in the state.
Here's a link to the sale prices/discounts by month:
https://abc2.nc.gov/Pricing/MonthlyReductions/3