Negative charge of methoxide anion Why is the methoxide ($\ce{CH_{3}O^{-}}$) anion negatively charged?

It has 13 valence electrons and has 13 free electrons. In spite of that the methoxide anion is negatively charged.
The negative charge is due to the unpaired electron in the oxygen atom, remained after all bonds(molecular orbitals) are filled. Oxygen has 2 unpaired electron in its valence shell and is singly bonded to carbon in this molecule. Hence being un-bonded, the other electron exhibits the charge.          

Check this link, hover the cursor on the $\ce{O}$-atom, you will get a graphical representation of the same.