OPENVPN with DigitalOcean?

Could you elaborate your question?
Do you want to install OpenVPN on a Digital Ocean instance?
Or are you asking if it's a good idea to have your own VPN on a Digital Ocean server?

Sorry, I didn't explain the question.

Yes, I mean 'having a self-hosted vpn on DO'.

It’s depends on your purpose. It’s good if you want to secure your connection of any public WiFi or secure your server by granting access only from your VPN IP. If you want to be anynymous on the web, or if you want to watch a lot of video /movie, I would recommend you to pay for a VPN.