Voting problem

I run a gaming server where players vote for credits but the problem is they get the credits before voting so they can just spam click for credits. I want them to get credits AFTER voting but I\'m not sure how to do this. I\'m willing to pay $25 but only if it\'s done the correct way. A friend of mine told me that there is an option how you could give the credits another way after they voted. if they vote for my site they have to click on my banner to get back to my page... this could be a link like [login to view URL] and if they go there they get the credits not before they click on the voting page. It would be nice if you could make it at least a bit safe with an IP-Restriction and a Referer-Restriction (for example: if they vote on [login to view URL] check on [login to view URL] if the referer contains [login to view URL]: if (strpos($_SERVER[\'HTTP_REFERER\'],\'[login to view URL]\') !== false) {//GIVECRETIDS} The website was not made by me, but another web developer who is currently not available so I may not be familiar with some things.