Of course you could use up scraps an make a patchwork version. As long as your starting piece of fabric is 3 times longer than it is wide, then do what you like!
Step 1: Gather What You Need
1. Fabric. Your piece of fabric must be 3 times longer than it is wide. This can any kind of fabric although bear in mind the thicker it is the harder it is to sew through a few layers. The red bag featured is actually made out of a scrap of Italian Melton wool which is 520gsm. This is a great project for using Japanese kimono silk. It makes a really elegant evening bag which isn't too large. The fabric in the picture is as I bought it. 140cm wide by 1m long. I cut it so it was 46cm long by 140cm.
2. Lining fabric (optional) . If you would like to line your bag (recommended for very thin or drapery fabrics) then a piece of your chosen lining the same dimensions as your main fabric. There are two ways to line this bag, I will explain both, but only one technique is demonstrated.
3. Sewing machine/ sewing thread and needle.
4. Pins/ mini clamps
Step 2: Decide on What Kind of Bag You Would Like to Make and Start!
If you are making a lined bag, then you can also finish the edges if you wish, but they will be hidden inside. The two methods for lining I will call lining method A (or LMA) and the second I will call Lining method B or LMB. LMA involves making the lining up separately and then sewing them together along the handles, turning through, finishing with topstitching. The lining hangs loose inside the bag. LMB involves sewing the lining and main fabric together at the beginning, then making up the bag with what is now one piece of fabric. The seams will be visible inside. As this is slightly difficult to explain I will take a picture of the inside of one of the bags to show what I mean. I'll post this pic in the next couple of days.
Start by lying your fabric out right side up (this means the side you want to show on the outside of the bag).
If you are doing LMB, then lie your lining fabric on top, right side down and pin together. Sew around the edge using a 1mm seam allowance and leaving a 15cm gap to turn through. Turn through and press. Sew shut the gap however you prefer (if you are lazy like me then it will be on your machine). Once his is done, then lie your new lining piece of fabric with the outside piece facing up. There are no special further steps.
All methods: Fold the fabric into thirds, right side over the middle third. Make sure you have got the length correct, you want to end up with a square, so check by folding over the left third. Keep doing this until you have got all the sections the same size (otherwise you end up with problems later!). Go back to having just the right side folded over the middle third. Pin along the top edge. Sew.
The two unsewn corners will make the handles.
That is the bag shape done!
If you are making the unlined version, then you will probably want to hem the edges along the handles. It is not essential. The handles can now be tied in a knot to finish.
For LMA you will need to do exactly the same with your lining fabric so that you effectively have two bags, one the main fabric and one in the lining. Keep the lining wrong side out and put the main fabric bag inside with its right side out ie, the lining and main fabric are right sides together with the lining on the outside. Line up the fabric along all the edges. Pin and sew the lining and main fabric together along the edges leaving a 15cm gap for turning through. Turn through and put the lining into the inside of the bag. Press the handle seams keeping the lining to the inside. Topstitch if you would like. You can tie the handles and finish now if you like! Or if you would like sewn handles then read the next step.
For the LMB, the bag is basically finished, and if you wish you can just tie the handles together and off you go! If prefer to sew mine together for strength, so if you would like to do that read on!
I hope this little i'ble is helpful and I hope it makes sense! If there are any bits which seems like jibberish or you would like more pics, then mention it in the comments and I'll do my best to rectify!
If you decide to make the LMA version but when you come to sewing the handles together find that the handle corners don't line up properly, then don't panic! Just line up the misaligned handles and trim them both so that they match. The shape will then be slightly different, but it is no real issue.