1) How much can a shared hosting take in terms of max members online?
Its not the hosting type thats going to bring up members to your board but just the popularity thats going to help you out.
2) Any good vps host to intro? Prefer a affordable price around $20 per month.
You can search and find a lot of hosts in the web host directories who'll be giving out an excellent hosting for $20. Also check out
Our Internet, they're great for us thus far.
3) Does vps space given include the os installed? Meaning do we need to install OS on the space given or there is already a OS there and we can just install application on the advertised free space.
The VPS will be provided with the OS installed by the Web Host itself.