Hiring a company to manage my amazon or run it myself?

I am getting to the point where I think it may be more worthwhile to have a company choose products for me to sell and manage every aspect of the business. I currently have about 250k in amazon products. What companies would be best for me to use? I am worried about buying large quantities of items and them not selling well and I would like to mitigate risk as much as possible even if I make a little less. Thanks