Metas: The Complete Series by Kelly Meding is a boxed set of the 1st four books in the Meta-Wars series. It's only $8.89 on Amazon. I was looking at buying some of the individual books because they were showing up as part of the Big Deal but they were still over $5 each.
This series is about superheroes. I haven't read any of these books yet but I have read her Dreg City series and really enjoyed them.