If I want to deploy a simple application using laravel forge I need to pay 10$ per month for registering + 5$ per month for digital ocean server + 7$ for private repository on github with total cost 22$ per month, right? Is there any way to deploy your application by paying only for digital ocean? I think 22$ per month and 5$ per month is a big difference.
If all you need is to deploy a simple application, then you could switch to Bitbucket for your private repos (it's free) and you could have a custom deployment method (e.g. log in to your Digital Ocean server and git pull changes every time) or use Laravel's SSH component (http://laravel.com/docs/ssh) or checkout something like https://www.deployhq.com/.
However, Forge is not just for deployments. It's supposed to help you manage your server (or servers!) and save you hours of googling while trying to figure out stuff like installing ssl certificates, upgrading php versions etc.
If you already know how to do all that stuff or if you don't need to do a lot of server administration, and if you have a single, simple app running on a single server, then you could consider the options suggested above.
Sure you can deploy your app only on your dc server.
But if youre not familiar with linux and dont have experience with server administration, php, nginx, ftp, mysql and that stuff ( and youre asking so you dont have ), then its a bad idea :)
This of course depends on how comfortably you are with doing the process manually. Forge automates a lot of things such as:
SSH Key setup & user management
Security Setup
Installation of all software
Git hooks/deployment
SSL Setup
CRON Tasks
Firewall
Communication between servers
Queues and workers and arbitrary daemons along with process monitoring
Server monitoring setup
Post-deploy scripts
Arbitrary scripts and "recipes"
more stuff I don't remember I'm sure
You can do this all yourself, but you need to decide if it's worth the money to you. Saved time vs automated.
I happen to know how to do all this and I still use Forge since it saves me a TON of time. It's value is up to you to decide.
Note that you aren't locked into GitHub either, you can use any Git server, potentially saving you money if you want to use BitBucket for private repos. Otherwise I wouldn't count GitHub as an expense if you'r going to pay for it anyway (in any solution). You can alternatively just not use Git to push updates as well.