You will find a lot of massage parlours and spa's in Bali. Prices for an Indonesian full body massage are around 100.000 IDR. (no plus service).
There are only a few massage studios where you can find girls offering you a happy ending massage. Happy end massages are also called plus plus service! The biggest chance you have to find a plus plus massage, is to work in the evening in Kuta area. Here you will find young girls with flyers which aren't directly in front of a massage parlour. Those girls will offer you plus plus massages or sexy massages. Those massage parlours are mostly in some small streets and the parlours aren't the most beautiful. The ladies mostly are asking 1 Million IDR for an plus plus massage. You can negotiate up to 50% discount.
Due to the fact that prostitution is illegal in Indonesia, girls are more hiding their business as in Thailand for example. You can meet freelancer girls in clubs or on tinder. The girls mostly are asking 1 - 2 Million IDR. You can negotiate a discount. But it's really hard to find someone who offers you a better price then 600.000 IDR.
The girls will mostly tell you that they don't look for love but for money, they will not get more into the details. You have to understand the message and offer them to help them with money...
A lot of Indonesian girls are coming to Bali to live a more open life. The most Indonesian islands are Muslim and Bali is Hindu. Therefore the girls are coming to Bali to live a life in peace without being under the control of there families or boyfriends.
Some girls are hoping to find a future husband which will bring them to a more richer country. But they are also realistic and know that the chance is low, so they are already ok to have a boyfriend of time which takes care of them during their stays.