Average cost of living

Just for basic figuring, you can do Bali budget style for around a $1,000 US a month...a bit more lavish, double it, and go from there.  Seriously, the range is incredible.  For example, you can do a home stay for $10 a day, or go all the way up to $1,200 a day for a 5 star resort.  It all depends on what you want.

You should keep in mind that you'll be arriving right at our full on peak tourist season, so you may have to do some serious looking around to find what's best for you.

Wont i be able to manage everything in 850 canadian $? Am not into partying and all. I coming there to have a healthy and fit lifestyle. Please help me!

I would suggest that you bring face cream and shampoo with you - surely that would be cheaper than having to shop around for it?
As for your other beauty requirements I imagine that would be another "how long is a piece of string?" Issue.

Bali is a centre for rather luxurious beauty treatments but when you go to these places they are mostly expat owned salons and they charge what the market will bear.

A lot of them advertise in the Bali Advertiser which you can see online then perhaps you could email the salons directly for the price of the waxing etc. And fingers crossed perhaps someone else that comes on the site will be a user of those services.

Have a look at trip advisor to check the price of accommodation for your dates - sorry to be unimaginative but that's probably the easiest way to do it!

As for food, if you are prepared to eat in un airconditioned warungs then your prices will be a lot lower than if you want aircon and food marketed to tourists.

I can't advise Kuta prices because I've not been to Kuta on my trips to Bali but in several locations, say, the mountains north of Ubud and the areas between Sanur and Denpasar (sitting in between the tourist areas) I have had a delicious main course for AUS$0.70 - but as Ubudian has said it will vary on tastes. Ubudian has lived in Bali for more years than I've had hot breakfasts so if he can't tell you straight out then your questions probably need to wait for more female members' responses. Good luck!