If you are Brazilian or have been to Brazil, then you (had damn well better) have a pair of Havaianas.
From the poorest people of the favelas, to the richest most chique real housewives of Brazil, everyone has Havaianas.
Used by most for going to the beach, Havaianas are a simple pair of sandals at heart – which means I wear them everywhere (although in Brazil, wearing sandals in some social settings can be considered “low-class” (however, I don't care)). You can find them for sale practically everywhere, and they will cost you between R$15 and R$30 (but there are certain styles that cost more).
According to the Havaianas website, the most recent inventory shows 79 distinct models of sandal and in 2007 they sold over 173 million pairs (that's ~6/second, aka a shitload).
Havaianas are known to many people as “those sandals with the Brazilian flag on them”, and although this description is in fact accurate, Havaianas offers up a selection must greater than the simple solid-colored “Brazil flag” sandals. They come in quite possible every style and design imaginable (my personal favorite being a Batman themed pair I saw on Morro da Urca, did not buy, and have been unable to locate ever since). Most have a rubber strap (that can cause some irritation at first if you aren't a sandal wearer), but some newer styles sport a fabric strap instead.
I have yet to wear through a pair (because they surprisingly easy to lose or get stolen), but they appear to be quite durable and my current pair is in its third year of abuse. Also good to note is that they can be quite slippery when wet – so take caution.
Plenty of knockoff versions exist (which is funny for a sandal that is so cheap in the first place), so if you care about the authenticity of your newfound Brazilian footwear, then you can shop at an official Havaianas store (which ironically seems to be the most expensive place to purchase them).
Get your own here!