Can do things pretty cheap staying on the beach at Bingin, I usually pay around $7 a night for a room at one of the warungs. Doesn't look flash but it's a bed and a place to store your gear. Hire a bike and the Bukit is at your finger tips. your kinda expected to eat some meals at the warung you stay at, but if you want a bit more variety there is some super cheap joints the locals eat at in the little business centres on Uluwatu/pecatu road. One little dodgy looking place does an epic keow teow for about 80 cents, and my bowels always survived unscathed

Suka Beach inne on Jalan Benesari is home if I'm staying in Kuta, clean simple and very cheap, and usually plenty of backpacker chicks around the pool to start an impromptu party.