I think it depends on how you interpret what an instructor or what a sales person tells you to have.
I've noticed that when in serious discussion with instructors they will relate equipment with conditions of a dive: i.e. Lake Ontario in summer 7mm with an optional hood, in the fall dry suit or 7mm with a hood & gloves mandatory, take 2 lights, etc. Cozumel lycra or 3 mil..., etc.; cold water regs vrs. warm water regs...etc.
You should make a list ( some sites have them) of exactly what equipment you will need to purchase for what you want to dive or learn, and what the course includes.
For instance, I did not know that my NAUI card was not included in my course (extra $35 CAD). As well as an additional fee for an instructor to sign off ($25 CAD/dive) on the open water dives (6 x $50-$75 CAD), which were also not explained when I signed up (advance $200 CAD)....but I didn't ask ;-)
Simply put: if the sales person at a dive shop told you how much you could spend before you started diving, you would probably would not start diving!
That said, now that I have all the goodies, and invested in the training, I am having a great time in the sport.
Best advice: RENT EVERYTHING BUT BASICS UNTIL YOU DIVE FREQUENTLY
Some expense items for a list:
Wet suit
Hood
Gloves
BC
Console/computer
REG
Octo
Tanks, valves
Lights
Booties
Fins
Weights & Belt
Mask
Snorkel
Dive table charts
Knives
Naui Basic cost
Naui Basic book purchase
Naui Basic open water dive
Naui Advance cost
Naui Advance book purchase
Naui Advance open water dive
Naui Advance open water dive cert
Travel, accommodations and food for all open water dives