I was there practically 4D4N, since I arrived late evening on 1st day, and left at 1pm on 5th day. 3 full days in Bali between that.
Total expenditure on food, transport, etc (excl accommodation) was 3.2mil IDR (abt $470) for 2 pax.
3D2N not a lot of time for you... perhaps consider going to Ubud on 1 day to eat the babi guling + walk around the market, and then Tanah Lot and neighbouring Pura Batu Bolong for sunset. Another day can go see Uluwatu temple + sunset at Jimbaran beach.
Kao Tim liao!