2000 BMW 323 car stalls every once and a awhile

For about the past 3 months or so, when I use my car more than twice a day, it will have problems to turn the engine over and then when it does, it will drive a few a feet and stall. I will turn the car off again, start it up again and then it will drive. It will feel lsuggish but wont stall again. For example, in the morning I drive the car to work and everything seems ok. If i take the car to go out for lunch I will feel the car is sluggish but it will drive without incident. Wen I drive to go back to work, then it will have problems turning over, but after a few "clicks" it will star only to stall after driving a few feet. I turn off the car and try again and it will drive without stalling but will feel slow - no pick up. When I leave to go back home, same thing happens - takes a few clicks to turn over, starts only to stall again, turn off the car and then starts again.
Any ideas why? What it will take to fix it and cost?
Appreciate any insights!
Sincerely,
Tony