Here are some tips I have gathered through living in Korea for about 4 years total.
I have mentioned if you need a membership card to get particular deals!
If you want me to research more about a particular road shop for best sales, etc. let me know and comment below!
Part 2: Duty Free Shopping Tips
As I have kinda sorta mentioned on my post about Dr. Jart and StyleNanda, and as savvy shoppers know, you have to shop at the Duty Free store for better prices on CERTAIN BRANDS.
For example, Belif is more expensive if you go to a store outside of the Duty Free. Even though it's a Korean brand, it's cheaper to buy it at Sephora or on Amazon. (Sorry, for the American perspective, but if you want to buy this great moisturizer and aren't from the US, I recommend you check the prices in your home country before coming to Korea, just to make sure!)
The other great thing about shopping Duty Free is that at Lotte Duty Free Stores, you get at least an additional 10% off for using a Visa card! (As you see below she mentions a specific type of Visa card, but it's actually for any credit/debit card with a Visa logo on it). Depending on the status level of your credit card and how much you're purchasing, you might also be able to save an even larger percentage!
However, my tip, which differs from hers (just because I live here and have seen the sale cycles), is if you are going to buy products from the typical "road shop" brands like Etude House, Innisfree, Missha, The Face Shop, Skin Food, etc., make sure you look out for their sale days and see if they correspond with your travel dates.
Typically, the stores I frequent the most, InnisFree, Etude House, and Missha, all have their sale dates around the same time, usually the last or second to last week of the month.
As I'm writing this now, InnisFree just had their "Green Day" event last weekend.
Innisfree doesn't necessarily have the best sales. However, to take advantage of the Green Day sales, you MUST BE A MEMBER. To join, you need to register with your Korean phone number and I believe your residency number and it'll be in Korean. So, if you don't have either of those, you should see if one of your Korean friends or friends who live in Korea has a membership you can use.
For MISSHA, when they have a sale, they HAVE A SALE. Right before Christmas, they were having a crazy 1+1 sale, which was great because there were a few staple items I needed, but not so great because you had to buy two of the SAME EXACT PRODUCT. Otherwise, their typical sales are 50% off, which are also great to look out for. You DO NOT need to be a member to take advantage of the sales.
Etude House has pretty good sales if you're a member, so sign up for that if you have a chance. Also, the really big payoff is around your birthday, you get crazy discounts. Last year, there was some crazy math stuff the employee did for me on my birthday and she was able to bump up my status to like the crazy high status with the best discounts even though I only bought two items. It was crazy math, but it all worked out.
A tip for Nature Republic lovers, NEVER PAY FULL PRICE! Even if you know you MUST have x, y, or z item and it's not on sale at the beginning of your trip, wait until the last minute to buy it at full price. It's HIGHLY LIKELY that the product will go on sale! Seriously, I have never bought anything for full price at Nature Republic. Also for frequent visitors or people who live in Korea, don't get a Nature Republic point card. It's so useless. If you buy something during a sale, which is like every day of the month except maybe 4-5 days, you can't get points for it. Also even though they call it "membership days," you DO NOT need to be a member.
Aritaum also has GREAT SALES. I think they have their sales once a month or maybe once every two months. When they do, everything is up to 50% off. Again, you HAVE TO BE A MEMBER. These sales apply to items even like perfume, which are notoriously difficult to get a good deal on.
Korea Grand Sale
For my fellow "foreigner" residents in Korea or even Korean citizens, you may remember I posted about the Korea Grand Sale, which is on right now. To take advantage of the additional "foreigner" discounts, you must use a foreign credit card! So, if your bank charges fees, make sure you factor that in to see if it's even a good deal to buy right now or wait for the next sale at your favorite makeup store.