This sounds like it is an excellent science fair project idea. Doing a carefully controlled experiment on a basic procedure that many scientists use for their research is definitely a worthwhile idea. Progress in science is made one experiment at a time, so I would encourage you to continue.
The Wikipedia article includes some background information on SDS, and reference 6 is a link to a database for household products that include SDS. Please note that you will have to search using all of the alternative names for SDS, such as sodium lauryl sulfate to find all of the products that contain this detergent. http://en.wikipedia.org/wiki/Sodium_dodecyl_sulfate
You would need to look up some of these products and try to pick one that does not have any other ingredients. If you can find one that does not contain other ingredients, this would be a perfect choice for your experiment.
However, it might be best to try to purchase the pure reagent grade SDS, even if it means filling out the forms. Using the pure detergent would ensure that you would not be including unknown variables in your experiment with the reagent.
Here is the information from this website about the rules for projects involving hazardous chemicals.http://www.sciencebuddies.org/science-f ... chem.shtml
SDS is a detergent and while it would be a good idea to wear safety glasses and gloves when working with the pure substance, it is not particularly hazardous, so I don’t think you would need special approval for working with this reagent. However, do check with your teacher and go ahead and submit the approval forms if there are any questions about the requirements for approval. Your project could be disqualified at judging if it is entered without required approval. http://www.sciencebuddies.org/science-f ... chem.shtml
Here is an material safety data sheet (MSDS) for SDS that includes precautions for handling this chemical. http://www.sciencelab.com/msds.php?msdsId=9925002
So what are you planning to do for your experiment? How are your going to measure your results?