São Paulo [1] attracts many more business travelers than tourists. So, many of its hotels are multinational and local chains that, while big on amenities such as work stations and wireless Internet, are often short on charm. A good number of them are located in far-flung but up-and-coming business hoods such as Brooklin and Berrini, which are convenient for getting to and from airports and meetings, but not so useful if you want to explore the city. You’ll also find accommodations around Avenida Paulista [2] (much better for your purposes) and adjacent Jardins [3].
The city boasts a surprising array of world-class, decadently luxurious hotels (even more than Rio [4]) that are great for living it up. Meanwhile, cheaper lodgings are available in Centro [1], which is slowly undergoing renovations and beginning to offer more interesting options, but at night the area can be rather dangerous. Many of the fancier hotels offer great discounts.
Ironically, rates are often cheaper in summer months of December–February (high season everywhere else in Brazil [5]) since this is when Paulistanos head to the beaches. You can also get impressive discounts on weekends—when business travelers are scarce. In fact, in an attempt to fill rooms, many hotels offer weekend “honeymoon” specials that seduce couples both married and otherwise.
Links:
[1] http://www.moon.com/destinations/brazil/sao-paulo/sao-paulo-city
[2] http://www.moon.com/destinations/brazil/sao-paulo/sao-paulo-city/accommodations/avenida-paulista
[3] http://www.moon.com/destinations/brazil/sao-paulo/sao-paulo-city/accommodations/jardins
[4] http://www.moon.com/destinations/brazil/rio-de-janeiro/rio-de-janeiro-city
[5] http://www.moon.com/destinations/brazil/discover-brazil