São Luís

Budget

Budget
$
Solar das Pedras
Rua Da Palma, 127
Dorm bed R$ 25, double R$ 60
Budget
$
Pousada Cantaria
Rua da Estrela, Old Town
Double with fan R$ 50
Budget
$
Hotel Lord
Old Town
Double with fan R$ 65, also air con.

Decadent

Budget
$
Pousada Maranhense
Old Town

Here people mostly pay by the hour, but you might use it in emergencies.

Budget
$
Pousada Beira Mar
Single R$ 25
Right by the bridge

Basic, small rooms

Budget
$
 

There is a youth hostel in Old Town that also offers singles, doubles and family rooms:

Budget
$
Pousada Internacional
Rua da Estrela, Old Town
+55 98 3231 5154
Single R$ 25, Double R$ 40, shared bathrooms. This old time LP favourite seems to be pricing itself out.
Budget
$
Pousada Reviver
Old Town
+55 86 3231 4465
Double R$ 25, also dorms and larger rooms.

Bright and clean, high ceilings. Shared bathroom. Kitchen. No breakfast.

Midrange

Midrange
$$
Praia Mar Hotel

(http://www.brazils-hotels...) - nice rooms right on the beach, good food.

Midrange
$$
Solar dos Nobres
Single R$ 50
Southeast of the center

Plenty of options within the Old Town, which is where most visitors wisely choose to stay. If you for some reason prefer a beach, Calhau has many pousadas no budget options, beach bars and a few restaurants.