Guatemala is a place for shopping, it does not matter if you are looking for local handcrafts, or the latest in modern clothing. Most capitals of the different departments of the country have modern shopping malls, and almost all tourist destinations have handcaft markets. Antigua Guatemala, Chichicastenango and Guatemala City maybe are the best for handcrafts. Now if you are looking for modern everything, your best bet is Guatemala City.
Flea market equivalents can be found everywhere. One of the most famous places in called La Litia (19 calle 0-10 zona 1, Guatemala City), is like a dollar store, but with more variety in prices and things; now the whole area is full of stores like that. Another famous place to shop in Guatemala City is Plaza El Amate where you can find movies, music, remote controls, soccer shirts, and a whole lot more. There are famous used clothing stores called Pacas (more exactly the lot of clothes is called like that), being Megapaca the most famous of all, where you can find used clothing ordered by size, gender and type, and sometimes new clothing also (Marshalls and Ross style).

If you are looking for something more formal, there are first class shopping mall also, like Miraflores, Okland Mall and Portales, that have everything a first world country citizen might need, including world class cinemas; and everything in between.