Public Relation is all about getting people to know about who you are and what you do. It will help groom perceptions and create a positive image of your company ‘personality’. How much time and money you spend on PR depends upon how satisfied you are with your current image and how important it might be to improve it. Naturally, the more you put in, the more you’ll get out.
For most companies PR is not the top marketing priority, but sensibly used it has a valuable role to play. Many firms do it themselves so most of the cost is in time, rather than money. Monitor your results, take press cuttings and form a judgement on whether the results justify the effort and expenditure. If you do opt for DIY bear in mind that you are unlikely to do the job as well as a professional.