Thanks for giving your ideas.
Here i wish to add another ideas.
1.Google Adsense
2.Blogging
3.Affiliate Marketing
4.Domain reselling business
I would suggest domain reselling business is the best one for getting money .Because i am earning lot of money through online by domain reselling business.I bought domain name reseller account from GoResellers.com .They provided good technical support .Here you can get bulk domain names at affordable price,So that sell your domain names and make money through online.I hope to help you.