Three sentence movie reviews: Teen Witch
I was watching this 1989 feature for period details, of which there were many. However, unless you also are interested in period details, I cannot recommend this movie, as the plot is insipid and the soundtrack is horrendous.* And someone could probably write a thesis about movies portraying witches that end with them giving up their powers.
Cost: free from library
Where watched: at home.
*Interestingly, the acting is not bad.
poster from: http://www.imdb.com/title/tt0098453/