If you want cheap shoppin places I suggest below:
1- Beyoğlu İş Merkezi – Taksim
It is located on Istiklal street. Really prices are very good!
The adress is Adres: Asmalı Mescit Mh. İstiklal Caddesi No: 187 İstiklal Beyoğlu İstanbul
2- Terkos Pasajı – Taksim
This one is crazy place like open markez on Istıklal street. Cheap cheap cheap! You can find a tshirt for 5 Tl (2 Euros) Adres: Asmalı Mescit Mh. İstiklal Caddesi, Terkoz Çıkmazı Sokak, Beyoğlu-Taksim/İST
3- Beşiktaş Çarşısı Sinanpaşa Pasajı – Beşiktaş
This is located in Beşiktaş and if you ask someone, they will show.
Adres: Hasfırın Cad. Sinanpaşa İş Merkezi No:5 Beşiktaş
4- Opera Onur Pasajı – Kadıköy
This is located in Kadıköy on Bahariye Street.
Adres: Osmanağa Mh., 34714 Kadıköy/İstanbul
Also open bazaars can be a option.
Also there are big AVM’s in Istanbul. Below you will find them
Akmerkez Shopping Center
This four-storey mall with almost 250 stores covers an area of 180.000 sq meters.
10 am and 10 pm every day.
Address: Ulus Caddesi No:3, Etiler – Istanbul
Istinye Park Shopping Center
Spread out over an area of 242.000 sqm, the shopping center offers a variety of outdoor and glass roofed indoor sections such as a green central park, Fashion District, street side shopping, a kids’ entertainment center of 1.500 sqm, Hillside Sports and Leisure Club, The Bazaar — an area inspired by historical Turkish architecture — and 12 movie halls, one of which being IMAX 3D.
Address: İstinye Bayırı Cad. No: 73, Sarıyer – Istanbul
Kanyon Shopping Center
As a four-storey shopping center located in the financial district of Levent, the 37.500 sqm shopping center has 160 stores among which Turkey’s and the world’s most selected brands, gourmet restaurants, cafes, a health and sports club and movie halls.
Address: Büyükdere Caddesi No:185
City’s Shopping Center
City’s concept is described as a Life Style Center. It sure deserves this stylish title, considering the variety of the stores, cafes, restaurants and the vital 24 hour six-storey parking service it provides to the populous area.
Address: Teşvikiye Mahallesi Teşvikiye Caddesi No:162, Nişantaşı – Istanbul
It includes big stores like IKEA, the sports store Decathlon, Praktiker, several technology stores, 62 domestic and international clothing and shoe stores, 15 cafes, 34 restaurants and 10 movie halls.
Address: Kocatepe Mahallesi,Paşa Caddesi, Bayrampasa – Istanbul
Galleria Shopping Center in Istanbul, Turkey.
Galleria Shopping Center
It has several elite stores, restaurants, movie halls, a bowling hall and an ice skating rink. Galleria was recognized as the world’s most outstanding mall in 1990 by the International Council of Shopping Centers (ICSC) for sophisticated blueprint design, rapid construction, and unique structural features.
Address: Bakırköy Ataköy arası sahilyolu, Istanbul
Metrocity Shopping Center
A four-storey shopping center housing 140 stores located in the finance district of Levent. Teflon coated fiberglass fabric was used for the roof construction, which brightens up the shopping pleasure.
Address: Büyükdere Cad. No:171 1. Levent