there are a few other cheap(er) places where you can try haggling but are unlikely to make them budge, one guy tried for a day and then gave up. overall it still ends up pretty cheap.
the two other main places are right next to club ventos, cheapest one is run by a guy called johnson, cant remember other dudes name but if you go there you get wifi...
some people carry their kit from their pousada everyday..
If you get a good price on accommodation you will end up spending the same to live as for board storage. I wouldn't worry about trying to book, unless you know someone, the best way for both storage and accommodation is to turn up and ask around/haggle. maybe book a place for the first 2 nights...
Al