If you want to avail guest posting packages for your website, there are certain aspects to consider. Firstly, not all guest posting services are created equal, and you need a company that can understand your niche and get content posted on authority sites. Secondly, the whole process of creating content ideas and writing posts should be a customized one, where the focus should be on your website.
It is always a good idea to consider placing a small order, just to understand if a particular service fits your requirements and can generate quality content. Since the costs are decided per post, you can always switch between services.