may i know which supermarket or place can buy Indonesia local food and souvenir in cheapest price in medan?any must buy local food recommend for traveller?
there are souvenir shops on the road close to the airport.
also you can find souvenir shops in the departure area (landside) of the airport. more expensive but not too bad.
Can also try Smarco at Ringroad City Walk.
In central Medan there are some streets exclusively selling local cakes for souvenirs, e.g., Jalan Mojapahit for Bika Ambon (tapioca sponge speciality of Medan) or lapis legit (layered sponge cake)
other than what have been mentioned "bolu meranti" is the trademark of medan. its a swiss roll and extremely popular, its located at jalan kruing, all taxi driver will know the place. get there early in the morning to make sure you still got the choice of all the flavour
other thing can be found at jalan mojopahit, such as markisa (passion fruit) cordial
for something that is more local you can try hitting the local wet market such as pasar rame (jalan asia), pasar beruang (jalan beruang), pasar hindu (jalan hindu). beruang and hindu only open in the morning