1. Try Facebook Ads
2. You can hire a person over sea on India, vietnam, china. $100 for 4000 likes or $300 for 10,000 likes. Go to Google and search Free Lance , Script Lance ...
3. Some guy on craiglis do this like service too.
4. You can invite your friends help you like. I have like 2000 friends any time I create some thing, just spend some hour invite them , and tell hey my best friend, this like page for me.
hope it work