If you're using Laravel check out https://forge.laravel.com/.
It makes it super easy to get up and running on Digital Ocean and http://laravel.com/docs/homestead provides a quick and easy VM to match what forge sets up on Digital Ocean.
Plus it's easy to setup multiple small projects on the same droplet. Forge is $10/mo but it supports Laravel and does save time setting up and configuring Digital Ocean along with easy deployment.
I started out with $5 droplet for my projects. Now one of my project that gained traction is on $10 droplet and rest still on $5 droplet.
Personally I avoid any PaaS/IaaS that require custom development hooks specific to their platforms to maintain my operational and hosting flexibility.
Could anyone explain why DO is becoming so popular?
AWS integration is complex due to multitude of services priced separately and need to be integrated separately. For early stage projects, this creates unnecessary complexity. The costs of these services quickly add up too.
As you embed more and more AWS services into your projects, you become locked in and unable to migrate off quickly. That is when AWS tells you to bend over and empty your pockets. You lose flexibility to move.
I have primarily investigated minimal of services on AWS and DO and found DO to better and quickly fit my needs.
If you can swing a static+javascript. Hosting on github pages seems to be popular, or AWS S3+CDN.
But if its a proof of concept for a relatively light footprint and low performance app then heroku would easily do the job.