I'm relatively young (31) and learned to fly last year. Out of all activities I've ever been involved in (sports, programming, executive life, teaching, etc.), flying has BY FAR made me most aware of my mental state and thought process. Nothing I've ever done has made me feel so task-saturated and consciously aware of how well (or poorly) I was coping with a cognitive task.
Not only can it sometimes be a very task-saturating environment (especially single-pilot IFR flying), but the added "nerves" of flying make it a perfect combo for you to become hyper-aware of yourself in a way that I hadn't yet experienced. The most interesting part of the whole ordeal for me has been to see my progression in terms of how my brain could handle the tasks at hand. At first, I remember intently listening to the weather report on the radio only to IMMEDIATELY forget the information I had just heard, such was my cognitive overload. Now, I can be in the middle of clouds, seeing nothing, punching information into the flight computer while hand flying the plane listening to ATC in one ear and talking to my passenger on the other. To have been acutely aware how slowly my brain adapted to the new demands I was placing on it was incredibly interesting.
Depending on rental and instruction costs in your area, how frequently you are able to fly, and how much time you spend studying and preparing, total cost to obtain an FAA private certificate will be somewhere in the range between $8,000 to $12,000. You'll pay as you go per flight hour rather than writing a single check up front. People have been burned writing checks up front, so I wouldn't recommend that you even consider it.
Under Federal Aviation Regulations (FAR) Part 61, a student pilot is required to have a minimum of 40 flight hours to take the practical exam ("checkride") but also an endorsement from your Certificated Flight Instructor (CFI) that you are ready. I have heard that the U.S. average is 70-something hours. An alternative is FAR Part 141, which has a highly structured curriculum that the FAA approves. Part 141 programs have lower required minimums for flight hours. Part 61 flight schools have more of a mom & pop feel.
Elsewhere I wrote a detailed breakdown of the possibilities for Part 61 training that may be useful to you.
You have choice of your aircraft rental rate (ac_rate above). Choose the cheapest available and that can carry both you and your CFI along with required fuel. The Cessna 152, a two-place slow trainer, in my area rents for just under $100 per Hobbs meter hour "wet" (fuel included) but only has 574 pounds of useful load. Your or your CFI's size may push you into a Cessna 172 or Piper Cherokee. The Hobbs meter ticks only while the engine is running, not by wall clock or wristwatch time.
Your next great influence is over total flight hours that you will require, solo and dual (i.e., with a CFI). Flying frequently will minimize forgetting and retraining. Be diligent about required reading and study that your instructor will assign. Rehearse maneuvers, checklists, procedures, etc. ("chair flying") at home before and after lessons, on bad-weather days, and whenever you can.
Being a member of AOPA can get you a discount on your knowledge test ("written") fee. Gear may include a headset, view-limiting device (hood or foggles), E6B, plotter, flight bag, and Electronic Flight Bag software such as DroidEFB or ForeFlight. If you're concerned about cost, borrow or buy used. You can get a decent headset new for under $200. Foggles, E6B (a circular slide rule), and plotter each go for less than $30 new.
The checkride fee you're probably stuck with ($400 to $800) because an FAA contractor known as a Designated Pilot Examine (DPE) will have to conduct your checkride and judge whether you performed the required tasks and maneuvers according to the Airman Certification Standards (ACS), and there are only so many DPEs per geographic area. You may be able to shop around for the medical exam fee ($100 to $200), but similarly you have to visit a physician with the Aviation Medical Examiner (AME) designation to get your medical certificate ("medical").
Good luck! Pilots always love talking about flying, so come back with more questions.
Not only can it sometimes be a very task-saturating environment (especially single-pilot IFR flying), but the added "nerves" of flying make it a perfect combo for you to become hyper-aware of yourself in a way that I hadn't yet experienced. The most interesting part of the whole ordeal for me has been to see my progression in terms of how my brain could handle the tasks at hand. At first, I remember intently listening to the weather report on the radio only to IMMEDIATELY forget the information I had just heard, such was my cognitive overload. Now, I can be in the middle of clouds, seeing nothing, punching information into the flight computer while hand flying the plane listening to ATC in one ear and talking to my passenger on the other. To have been acutely aware how slowly my brain adapted to the new demands I was placing on it was incredibly interesting.