SimsVIP have unearthed a statement, published last November, by SimGuruDrake regarding EA’s policy towards custom content locked behind paywalls.
In short, it’s forbidden to charge for custom content for the Sims. Fortunately, there aren’t as many paysites around as there was a few years ago, but a few still linger around like a bad spell. Newsea, Leo-Sims, and SIMcredible spring to mind, but there are certainly others.
Sites like Around the Sims and The Sims Resource have come up with a good method of monetizing their Sims content. Rather than charge for the content itself, they instead charge for the convenience of being able to download quickly.