hi,
if u just study in detail with refernce to text books and dont only depend on decks and old papers , ull be fine.
i really dont think u need to waste that kinda money.. cause its really not impossible if u study ahrd , in detail , understanding every topic rather than mugging up facts.
in saying this from experaince. i know decks are not adequae , refer to text books.. read in detail.. refer esp topics u dont know..a nd ull be fine... u will definitely do well...