Can any one help me i would like a visitor counter on my site but not sure how? do i have to buy more software??

lots of free ones online, google web counter or visitor counter and you should get fixed right up.

So long as you don't need to count more than about 500 visitors per week, www.statcounter.com is a free one. You just decide on a number of settings and then pick up a snippet of code to slip into every page you want to be counted.
As David says, there are plenty about, but don't take the results too seriously as you can well be counting your own pages too... or someone coming back in after a cup of coffee. Your own server might have a counter for you to use... check that out.
There are certainly some that you can finely tune to collect just the information you need, but look around and think carefully why you want a visitor counter. And my advice is to NOT have the counter on view but just to view the results yourself. Visible counters are a bit like a double edged knife which can even put your site visitors off.

Google analytics its the best thing ever ! i strongly recommend it !
www.google.com/analytics

Check this out
http://en.wikipedia.org/wiki/Google_Analytics

bravenet.com has lots of free apps also

Hmmm I think I'll drop the idea of a visitor counter, it'll be embarrassing for me, with it showing only 7 hits a week (of course there'll be more hits if I check my on-line site more than once a day )

LOL
Zipper... with statcounter, you can include a hidden counter! So only you see the numbers and noone else!

Google Analytics is hidden as well
a display counter is outdated IMO