[wtvanhest]

It depends on how much you want to do yourself.

Heroku is easiest and relatively cheap until you scale. (Great problem)

Lots of people seem to use AWS. My limited understanding is that it is marginally more difficult to implement than heroku.

You could also go with someone like Linode. I would only go that route if you have implemented before. There is a learning curve and if you are trying to get the site up quick, I would go with a different option.