Although the characters read "Da Ming Xuande nian zhi" (I think)on the two larger rice bowls, which translates to "Made during the Xuande reign of the Great Ming dynasty", they are probably modern made. You can't judge Chinese porcelain based on the marks, crazing or the aged look. All of these things can be found on modern pieces, and there are tons and tons of it. You have to study and handle that stuff for years before you can be proficient at identifying it.
Myself... I stay away from it because I know absolutely nothing about Chinese or Japanese porcelain except that most of it is very decorative. For $5, you didn't lose anything but I don't think your gonna hit the lottery with them either.