I looks like it is a glitch. One example is the tax. I had worked, and then it didn't. I went into the cart object, and there was no tax rule defined. So I set it up again, and then it worked again.
But it seems to be some glitch that repeats itself. Just now the cart page stopped working again. The tax is there, but it separate different products into different lines. Again it only brings up the first record from the database. Also when I go to the detail page, it shows the right product name and all the right info, but for the picture it shows the picture of the first record in the database. Very weird.