Krume Bogevski
Google
This is the most traditional thing to get your relatives if they like coffee! It's right across the entry to the Egyptian/Spice Market (Misirli Carsisi) and has been there for like 150+ years!
Have been twice to the Grand Bazaar area so far and bought 5 x 100g coffee packs to take home as souvenirs. The price is really affordable and I recommend getting it for your friends and family.
The staff is really busy, so don't expect a lot of attention, but taking into consideration that they sell only coffee and cocoa, what would you need? Just see the price list for the amount you need, tell the boys how much you need and pay. Be prepared to wait for a few minutes.