This is a very broad question. Heroku has dead simple deployment for Ruby applications; see the pricing page to play with options. Also it's free for very low u

This is a very broad question. Heroku has dead simple deployment for Ruby applications; see the pricing page to play with options. Also it's free for very low usage applications, but scales up easily. VPS offering from Amazon, Linode, Rackspace, Slicehost, etc have a minimum threshold around $25-ish.