Its difficult.People will treat it as spam.You can send well written messages and that too only if your selling particular products.Social media is a good tool but not everyone uses the internet or sites like Facebook,twitter etc.SMS must be well written and must target your audience.Sending bulk SMS can be risky.If you live in India you could buy the numbers from agencies and send SMS only to a particular audience.It may work in some cases and some cases it might not.IT is not a costly affair even then putting this on twitter or advertising it there will give you good results as well
Keep in mind some people don't pay for text messages, so if you send them one, it will cost them money. They might not be too happy about that and these days with social media, whatever you are trying to sell, your reputation could become horrible.
You should know its technical side....
Thanks...
