Part of that depends on your goals. If one of the best ways to draw people to your website is to build your brand and increase the number of people that know your company exists, how much is that worth? If you are seeking volunteers for an organization and by tweeting and posts to facebook leads to that, how much is it worth? If asking for donations brings in some money, money that you would not have seen otherwise, isn’t that important? At the end of the year, figure out what you’ve spent on the cost of outsourcing your social media and see if any or all of these areas have improved during that time and you will know right then that social media is worth the time and money. Ideally you’d be able to measure exactly how much you spent vs how much you earned in dollars and cents but with social media that can be tricky. There has to be an overall analysis at the end of the year of increased brand awareness, increased number of hits to your website, increased involvement of volunteers and of course, increases in donations. In only a few months time and with only a few hours per week I’ve seen huge increases in brand awareness, new visitors to the website, retweets on twitter and fans on facebook and already some donations that would never have happened had I not been actively using social media to spread the word and promote the cause.