At our startup (we're still stealth, so I don't want to announce it here), we found that way more people signed up when we kept the signup as frictionless as po

At our startup (we're still stealth, so I don't want to announce it here), we found that way more people signed up when we kept the signup as frictionless as possible, because our app doesn't sound amazing in the marketing language but it really speaks for itself once you start using it (I'm thinking of my reaction to the iPhone back in 2007 - "so it's like a smartphone without a keyboard? How does that work?"). Once we get people using the app, it is very easy to get them to put in a credit card. One way we encourage them to put in a credit card is with a free trial countdown at the top of the screen that gives them special offers if they put in a credit card on certain days (e.g. 14 days left, get a freebie if you enter a credit card). One thing that is unique about our app is that it has residual value even if you don't convert, because you can opt in to still receive alerts. Each alert gives us another chance to convert a former free trial, and to date the record for latest conversion is 100 days after trial ended.