I've priced out several and all are within 150%. Shipbob is the closest at 10-20% more expensive than FBA, but depending on your product it may actually be more cost effective. I need them to pick and pack several items, since I sell my stuff individually as well as in kits (boxes of multiple items, which are vastly more popular than people buying individual items), and they include most of the cost of building out those kits in their shipping fees.