I have an inexpensive large folio holder for the large pieces, this way I can lean it up in the closet behind clothes. I would not recommend using poster rolls if possible. Also, I highly recommend that you frame and display your best pieces in your house. Don't be shy, be proud of your work! Think framing is too expensive? I stock up on 11x14 sale frames (costo often has 3packs)... I also pick up odd sized frames from the frame stores. Sometimes you can snag extra mat board cheap. I have a $100 mat cutter that I can cut my own mats if I am really ambitious and want to display something a certain way. Be sure to check for framing at Art supply stores, not galleries, the art supply stores cater to students and starving artists and the pricing is usually very good! Try to get archival quality mats for your original work, and if you plan to display your work in a sunny location I would consider archival glass as well. You need to preserve what you've done, it might be priceless one day.

If you plan to market your art, presentation of your pieces is critical to success. Matting is the perfect way to make your art stand out.

Since I do not have a studio dedicated to my artistic endeavors, and, I often like to take my supplies with me on the road, I have come up with clever ways to keep all of my art stuff "contained"
I don't ever find that I want to spend a day using "all" of my various mediums. So I found it easy to break down my supplies by type. I also try to have any multiple copies of shared items in each container so I don't go off and forget something critical, like an eraser, or say masking fluid.
Below is a breakdown of my storage tactics...

I bought two different sized fabric folio zipper bags, one for large pads, and another for smaller pads. I also have a large clipboard in lieu of an easel. I am still considering an easel, but so far have found the working flat with watercolor is the best way to go...
One other paper tip, you can never have to much paper. Ask for paper for gifts from people if you are poor, or an art supply gift certificate. The more paper, the merrier!

I have everything in a storage box that is small enough I can toss it in the car or the motorhome at any time. I will admit that most recently I kitted up my Watercolor supplies and I prefer a container with a handle to carry things. My Drawing box is just a storage box.

I did some research on the web before I went to purchase my watercolor supplies. I read about the various types of watercolor paint options. The art supply store carries the tubes, cake and semi moist paints. I purchased the brand Yarka in tubes. So far I am happy with how the paint works on the paper but I do not like trying to open the tops. they are so small. So, I went back and bought a small set of semi moist to try. I will report on which I prefer overall after I experiment more with the semi moist.

Another reason for purchasing the semi moist is that I wanted a small travelling watercolor kit. I bought minimal small items to put in a small case I have. That way I will be prepared for any opportunity to paint. The pad of paper is only 5x7. In my kit I have scans of a couple of photos I can use if where I am doesn't have any potential subjects to paint. Remember I do not do well painting something from memory, I need it in front of me.

Eventually I would like a small 4x6 photo printer for my digital camera. I can bring that say in the motorhome for printing subject material while on the road.

2 containers. I have a large container for my main supplies, and then I bought some very small items for taking on the road if I do not have much room. I am using briefcase'ish (school supply) containers, with handles for easy carrying.