[1] https://azure.microsoft.com/en-us/pricing/member-offers/bizs...
[2] https://aws.amazon.com/start-ups/
[3] https://www.soyoustart.com/en/
[5] any other provider (softlayer,packet,...)
[0] http://dokku.viewdocs.io/dokku/ (Heroku self-hosted)
[1] http://rancher.com/ ('Point and click Docker cluster ')
[2] https://www.mindmeister.com/389671722/open-container-ecosyst...
[3] https://www.ansible.com/ (Server provision)
Also, using AWS doesn't necessarily imply IaaS. You can use Elastic Beanstalk.
If you want an early head start with something like containers, then Kubernetes is nice and 1.4 has some good features to make it easy to scale across clouds/on-prem/colo in the future.
As for which platform? IMO the most important factor is which platforms the developer(s) are most comfortable/familiar with. The last thing a new SaaS startup needs is to waste time while the engineers figure out a new platform they've never used... Doesn't really matter how easy or cheap it is to deploy if there's no product ready to deploy ;)
Hetzner is cheapest but the other two have private networking.
If I didn't care about cost I would just use AWS or Google.
Cloudways/Heroku because I don't want to spend my time on bothering with server management.