Bags are nice, and bags with a zippered pocket inside are even nicer. When I make a bag for myself, I usually like to add a pocket to keep my keys and cards safe while the bag can preferably be open or closed with a single button. Maybe you think zippers are difficult to sew, but I can show that they are not necessarily. (Changing a zipper for boys' jeans is on the top of my least favourite list.)
EDITED TUTORIAL
First you need to measure the zipper you are going to use. I prefer 18 or 20 cm, the length commonly used on skirts and trousers. Measure the teethed part only, and add a tiny bit like 2-3 mm.
Cut the pocket so the width is the same or more than the length of your zipper tape. The pocket can only be as deep as the distance from the zipper to the bag bottom. Draw a line as long as you just measured, about 3 cm from the top of your pocket fabric:
Pin your pocket fabric right sides together on the lining where you want the pocket. Now sew a square around your line using the side of your normal sewing machine foot as a guide. Make right angle corners and double stitch the ends where your drawn line ends.
Here is my square, you may need to click the picture to see better.
Then comes the exciting part: you must cut along the line. I start by folding the fabric in half across the line and cut a hole along the line somewhere in the middle.
Then open the fold and carefully cut along the line. When you are close to the end, cut towards each corner but be careful not to cut your stitches. Do this at the other end as well.
Then pull the pocket fabric through the opening, and finger press the seams flat. Pin the pocket on the lining at the corners, finger press the ends so there are no wrinkles. If this seems impossible, you may need to cut a bit more, but again be careful with the stitches. You could iron the opening to make things easier at the next stage.
Next take you zipper and pin it under the opening with the pins on the right side. Use your zipper foot if you have one. This can be done with a normal foot or a quilt foot as well. I usually stich the zipper down on both sides, so I started on the right side, with the zipper pulled down a bit so I can make a straight line. When I have sewn down to the first pin, I stop with the needle down, lift the foot and pull the zipper closed. Foot down again, and continue sewing close to the edge of the fabric all the way down, make a nice turn and double stitch across the bottom. Then change your zipper foot to the other side and sew across the top a double stitch, and finally down the left side of the zipper. Again, you can open the zipper for the first bit if your needle comes close to the zipper pull.
Here is the zipper on the reverse. Notice that I have sewn the top ends of the zipper tape together, this helps to sew a nice square seam when fastening the zipper.
To make the pocket, sew both pocket tops together above the zipper -the zipper foot is good for this as well. You need to fold the bag lining away and sew only the pocket fabrics.
Then join the pocket sides, and bottom, if you have a separate pocket back fabric (I had a long piece which I folded at the bottom). Stitch the pocket front piece (with the zipper) on the pocket back with right sides together.
The pocket is now ready, and you can finish your bag lining. You can make any bag pattern perfect for you by adding the pockets you need.
Here is my new bag made of the fabrics I bought in June. I have another one coming in white with purple dots.
A week ago the pied flycatcher babies flew out from their nice house. This last one took a long time, coming to the opening and going back in again.
Finally it made the decision, jumped out and ended up on a big branch about a metre from the nest. The mother came immediately and rewarded the baby with a treat. I watched them for about five minutes, but apparently the baby then knew how to fly, and they both vanished. I can still hear them almost every day, but they don't live in the nest any more.
The baby is almost the same colour as the oak, and with his or her back towards the camera. You can click the pictures to enlarge.