Have you ever tried setting google on book search. Keep looking and you may stumble onto some very interesting stuff you won't have to pay for...
 
http://books.google.es/books?id=VgVMkT2T5ggC&printsec=frontcover&dq=speak+english+fluently&hl=es&sa=X&ei=AxwCU46hOOn40gXHw4HoBA&redir_esc=y#v=onepage&q=speak%20english%20fluently&f=false

http://books.google.es/books?id=mjdxKEvI_pkC&printsec=frontcover&dq=write+in+english&hl=es&sa=X&ei=fRwCU_i1MuOn0QX7vIC4Dw&redir_esc=y#v=onepage&q=write%20in%20english&f=false

http://books.google.es/books?id=g5PeZC0JwFYC&printsec=frontcover&dq=sample+writing&hl=es&sa=X&ei=cBoCU8DnI6iT0QWdvIDACQ&ved=0CFQQ6AEwBQ#v=onepage&q=sample%20writing&f=false

http://books.google.es/books?id=xeTd0I-XPYIC&pg=PA12&dq=sample+writing&hl=es&sa=X&ei=cBoCU8DnI6iT0QWdvIDACQ&ved=0CFwQ6AEwBg#v=onepage&q=sample%20writing&f=false