I have met so many people that have started and "nearly" finished their pilot license training. The number one reason I've seen for failing to get the license is that they run out of funds. I planned on twice the minimum and still ran over budget.
The legal minimum to get a sport pilot license is 20 hours of flight. Airplane rentals cost about $115-$130/hr. Of those, 15 is flown with an instructor who charges $50-$70/hr. So far, we're at $3050-$3650 total. Sadly, those 20 hours is not nearly enough. Especially if you only fly on the weekends and are getting the license as a hobby. Plan on doubling the minimum number of hours.
Even with that in mind, you are at the mercy of the weather. You can't fly if it's windy or cloudy. Wind is created by temperature differentials which are created by the sun's uneven heating of the earth's surface. If there are no clouds, there's usually wind, if there is no wind, there are clouds. See the problem?
When learning a new skill, especially one as challenging as aviation, it is imperative to practice often. Mother nature often foils your plans. It took me about 55 hours in total to get my license. That included having to switch schools part way through because they didn't have any planes to fly. Remember, just like a driver's license, you have to go take your vehicle to the testing facility. The weather tends to change frequently, so by the time you get there and pass the verbal, it may not be a good time to do the practical portion. So you wait for the weather to calm down, but then the examiner will be on to their next examinee and you have to come back on another day.
All these scenarios are normal and a fact of life for a student pilot. Here are some tips to help reduce costs:
Do ground school on your own
If you are a person who can hit the books and absorb the material from textbooks or learning software, this is one way to save $400-$500. You'll be learning from your instructor while flying, but there are a lot of things going on, and your brain will be fried after an hour's flight. So it's best to come prepared.Use flight simulators
You can practice communicating with the air traffic controller (ATC) in flight simulator. There are things like VATSIM which is a network of student pilots and student ATCs. It has a very professional atmosphere. Flight simulators can also help you learn the nuances and steps of landing especially with a crosswind. It is time well spent.Do as much as you can with the engine off
Get the ATC information, set up the instruments, adjust the seat, discuss the plan for the lesson, etc. These are all things you should do while the engine is off and the Hobbs meter is not running. Remember, schools charge for the number of hours the engine is running, not the hours you rent the plane for.
Hopefully this information is helpful to you. I have some other tips on what equipment I use when flying that is as good as or even better than the name brand expensive gear. Let me know in the comments if that is something of interest.