Walmart offers Divergent on DVD / Digital for $5. (Amazon charges the same, although it's currently on backorder.) Opt for in-store pickup to avoid the $5.97 shipping fee. That's the lowest total price we could find by $5.
With Luke on this, not worth even the time it takes to watch these inane, manipulative, dumb teen fiction movies. Saw the first two and once they reveal some answers in Insurgent you realized you were dragged along for an answer just slightly better than the ending of LOST