It took us two years of trying different programs out but we've finally settled on a program that all of my children have come to love. (This is very rare since they are all so different.) The program is called Easy Grammar By: Wanda C. Phillips. This program is taught using the prepositional approach which was very different from the other programs we used. Taught by grade level. It After a few weeks, my eldest child asked me "Mom, why didn't we get these along time ago?" Priceless coming from my un-medicated "ADHD" child.
The program comes with the teachers edition which also contains student workbook pages. If you chose to you could simply copy student pages, but I wouldn't recommend. The student workbooks are affordable and cheaper than the ink. I would also recommend the daily review book that accompanies this set titled Daily Grams. This gives a one page, daily review lesson on various grammatical topics. We love it!