I just purchase a coat with the zipper in front but it sometimes get stuck any suggestion on fixin the problem

Answer 1

find a spare candle and rub ot on the teeth of the zipper, the wax should make it slide easier

Answer 2

You've probably run into this jam before: You're zipping up a jacket, and the lining suddenly gets caught in the zipper's teeth. Here's how to get out of it.
Instructions
STEP 1: Stop zipping as soon as you feel something is caught. STEP 2: Examine the zipper to locate the problem. The inner lining may be caught, so check the inside of the garment or sleeping bag. STEP 3: Gently pull the lining away from the zipper. Tug lightly if necessary. Pull at the lining, not at the zipper. Pulling the zipper tab up or down will worsen the problem. STEP 4: If any teeth became separated as you removed the lining, push them back into place. STEP 5: Run your fingers along the length of the zipper and push the lining away from the zipper to prevent future snags. STEP 6: Use a little force to pull the zipper to the bottom. Then rezip, making sure to avoid the lining as you go. Overall Tips & Warnings
If a missing tooth causes the zipper to get stuck, run the zipper quickly over the area of the missing tooth. The momentum will help the zipper stay on track.
If the zipper is sticking because it's worn or old, rub a No. 2 pencil along the teeth. The graphite will smooth out the rough spots.

Answer 3

Bar soap is a good method