How do I unclog my bath tub drain?

I have a bathtub that wont drain. Its on the first floor slab foundation. I have plundered, snaked and poured sulfuric acid down the drain. After a shower it takes about 5 hours to drain and its getting worse. I really don't want to call a plumber because we are broke right now. It cost $60 for them to come out. Please help!