Quick answer: The best time to visit Bali is April–June or September–October (dry, less humid). Expect a mid-range budget of about €50 per day. Visa: Visa-on-arrival (30 days, extendable) for most passports.
Why this window
Bali is bigger than it looks — base-camp by region rather than hopping daily. This 7-day plan splits between Canggu (surf/cafés), Ubud (rice terraces/culture) and the Uluwatu cliffs.