There was a similar question posted about 4 weeks ago and there were a variety of responses.
Average lunch of maybe nasi campur or babi kecap, expect to pay 20-30000Rp. Similar price for club sandwiches with chips. This of course depends on where you eat and what you eat as the little warungs are much cheaper than the bigger restaurants.
For dinner, if you go for something like a tuna steak or fish/seafood, expect to pay between 40-60000Rp. Steaks are about 75-80000Rp. Starters (soup, prawn cocktail, spring rolls) expect to pay between 18-20000Rp.
Cocktails are around 35-40000Rp, 660ml bottle of Bintang beer between 17-30000Rp, local wine about 40000Rp for a glass.
Candi Dasa is quite cheap for eating compared to other resorts, but it depends if you're eating somewhere like Vincents or Toke or the Watergarden which are quite expensive (still cheap by UK standards). I normally budget for £50 a day (leaving money left over for shopping, transport etc), although in Candi Dasa you can easily get away with £25 a day.
Didn't see an ATM when I was there, but there's a reliable money changer at the Post Office. Last week, exchange rate there was 16600Rp to the pound for travellers cheques, 16800Rp for cash.