Near 28 de julio (crossing via expresa) there is a big, commercial mall called Polvos Azules
where you can find a lot of clothes, shoes, electronics, domestics, video games (cheaper than other malls due to smuggling). Walk through the clothes area and you will be hassled by the clothes sellers who will tell you that they have your size, "tengo tu talla!
The price is probably s/.80-100.
Map belowhttps://www.google.com.pe/maps/place/Po ... 1929?hl=en
Good luck. Let us know how you did.