Hi Stella
I've been to Nusa Lembongan once, about seven years ago. I enjoyed it, for what it was (a very small island, 8 square kilometres in size, some spectacular views across to mainland Bali, lots of scuba diving/snorkelling/surfing, , no cars, etc). There are three main villages on the island (total local population about 5,000).
Even then there were several up-market places being built, but no shortage of cheaper alternatives.
You have to remember that most things are more expensive there because everything has to be brought over by boats from Bali.
"Night life" was very limited but I imagine there would be more these days, especially around New Year.
One could think of Lembongan as a kind of "miniature Bali", but without traffic jams, supermarkets and the like.
There were no ATMs when I was there. I gather that there might be some now plus a few money-changers, who will probably give poor rates.
I would be inclined to take enough Rupiah with me to cover my intended stay and only use an ATM/money-changer if I really had to.
Getting there is pretty straightforward from Sanur. The daily public ferry takes about 90 minutes, fast-boats take about 30 minutes.
They all leave from the bottom beach end of Jalan Hang Tua (the same street as the Grand Bali Beach Hotel).
Personally, I would rather go there than the Gili Islands. Gili Trawangan has been over-commercialised, IMHO.
Gili Meno is working on it, and I haven't been to Gili Air, so can't comment.
Getting off mainland Bali for New Year might not be as "silly" an idea as
Markit purports.
Fewer people, can watch the fireworks from a distance, but I'm sure there will be some on Lembongan as well.
I suggest that you look into the current available options on Lembongan. The following site might be helpful (I'm not sure how up-to-date it is).
https://en.wikivoyage.org/wiki/Nusa_Lembongan
Hope this helps.
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