Website visitors vs paying customers?

[Matt]

I'd like to know if anyone has any experience selling services or products or whatnot online. I can buy 10,000 visitors to a site for $9.99 (I'm buying from a company I've worked with for years, so I know where my visitors are coming from, ie what sites and all that). The site I'm directing traffic to isn't mine; it's my referral link to a site I'm hoping they'll sign up to.

I'd like to weigh cost vs potential income.

I make 20% of whatever these referrals make for life. I'd like to know if you have any statistics on how many people who visit will end up joining the site and actively using it. To make my $10 back, I'll therefore need these referrals to earn $50 total. Spread over 10,000 visitors, this seems easy (1/10 of a cent per person); but I don't know the statistics.

I realize that a lot of these people are just viewing the site for 15 seconds or whatever so they can get their fraction of a cent they were promised; and they won't even think about the site ever again. I'm figuring about 1/100 will actually sign up (Hopefully that's pessimism?) and out of those, only half will earn anything; the average, which I've found, to be about 50 cents. Therefore, it would seem that I'll make about $25 ($15 when subtracting the cost of the initial payment) but can anyone tell me if this is accurate at all?
Alternatively, for the same price, I could get 200 clicks on a site that visitors aren't going to rush through; this a site where the visitors will actually pay attention to the content.

[Vek]

You'll need some past statistics of the site you are sending traffic to in order to get a correct calculation of what you will earn.

In particular is the conversion rate of the site (how good the site is in turning visitors to customers). Without this information, you can only guess and that can give you misleading figures.