Hi There,
I live in Douglasville, which (as you probably know) is right next door to Dallas. I can get 121oz. jugs of 8.25% bleach for $2.95 at Dollar General. Read the labels carefully, they have two types and one of them is the much weaker 3% for $2.50. They also carry Chlorox brand but it is $3.50/gal. I'm not sure if that is the cheapest around, but I live very close to one so it is convenient for me and it works perfectly.
I just want to add that it will take some time to get the pool cleared up, probably two weeks once you start SLAMming. However, if you stay the course and follow through, your pool will look better than it ever has before and maintenance will become super easy. I'm a perfect example of this, I check chlorine and pH daily and adjust if needed, brush and vacuum once a week. I use about two gallons of bleach per week to keep the chlorine in line and that's about it.
What area of Dallas do you live in? I can come over and help get you started with the test kit if you like.
Tad