Get it at a data center. Even if they require payment in non anonymous ways you can use exchangers to anonymously fund them after washing the money securely. Just fill out bullshit information on their registration forms but try to make it seem legit / be legit info largely to get by any automated fraud detection. You might even need to get burner phone or pay somebody to do it, if you need a dedicated server. Dedicated servers are the hardest to get anonymously, they might even want scans of identification docs. Lots of anti fraud systems and such are in place when it comes to dedicated, but I have yet to find a hosting provider who had unpwnable anti fraud / anti crime systems in place it just is a huge pain in the ass. VPS are generally much easier to get. This way even if the hidden service is traced they hit a dead end. Of course always use Tor. If the hosting provider wont let you purchase with a Tor exit you might need to find an open proxy that isn't on their block list for registration. You probably will need to use an exit node that is in the country you pretend to be in, and you might even need to be able to get a text message or verification phone call to a cell phone registered in that country / produce scans of ID for that country (this is all for dedicated). There are also some bulletproof / anonymous specialty hosts that don't make you jump through a billion hoops, and most of them are in favorable geographic areas. But expect to pay out the ass for a bullet proof anonymous hosting plan.