Gemma Halliday blogged recently about selling her high heel mysteries as box sets, and now I would like to share some of her wisdom. She has been on the NY times best seller twice this year with her "box sets" and has adjusted the price several times to push sales. Number one rule - never give it away for free, as once they have it there's no need to buy anything else. Rule number two - less is better. If you have a 4 book series, box up three, and charge a little more for the fourth. Makes good sense right? Rule three- price it sensibly, at a lower overall cost than buying each book separately.
If possible have a 3D cover made, but a flat one will do. The books don't have to be a series, but they should have something in common - such as Rom/Com, Single Titles, Mystery, etc.
What you need to do is create one big file with say all three manuscripts, download it as usual on Amazon or wherever you choose, have your cover, give a brief description of what they will be getting, and voila, you have another pricier item to sell.
I'm going to give it a try with my Candy Bar series, and also with my 3 single titles. I haven't done this yet, but will report back when it's up for sale.
Good luck to you all.