Blue Point has a really nice room for 20 US$, but you can also try to get to sleep in a tent they have set up, which should be around 10 soles a night for 2 people.
Hotel Arrecife arrecifehotel.com has very nice quality rooms. $10-20 per night per person. Service is excellent, and english speaking. Hot water, some drinks sold in house, and overall not a bad place. On the quieter edge of town also.
