Well, I have made a bunch of tote bags in my time (all without patterns), and I realized that gemoetry classes didn't totally go to waste.
To make your bags, find a heavy fabric, like denim or something similar.
Fold it in two, right sides together.
Draw a square, slightly bigger than what you want it to be.
On the left or right side of the square, keeping the same height, trace a rectangle. This will be the depth of your bag.
When you have cut all of them out, you will have four peices - two squares, two rectangles.
Trace one more of the rectangles - this will be the bottom of your bag.
You can make the rectangles out of different fabrics if you want, to add a bit of funkiness.
If you are using a less strong fabric, you can do what I did with mine - sew on an equal sized peice of crafting foam, cardboard or any other thick, stiff material onto the bottom rectangle peice.
Now all you have to do is pin the rectangles to the sides of the bag squares, sew them together (the bottom is a bit tricky) and then hem the top of the bag.
Oh yeah, you might want to add on some handles made from a cord belting, attatching by sewing squares instead of just one lame line of stitching.
For the thread and all, just use regular denim needles, and there are even special denim threads you can buy for jeans. It doesn't really matter that much, actually. My advice - when working with denim or any heavy fabric, start off slowly, and when you are turning up edges and sewing over an exsisting seam, when you first come up to it, stop your machine and just use the wheel and get over it using that method. If you use your wheel, you can jam up your machine. Last of all, don't forget to clean it before or after doing a large project like that so you don't have as much of a risk of messing up your machine.
I learned the hard way.
Hopefully this helps.
Sorry if it's hard to understand