TES [Recommended: Especially for the UK Market]
We actually sell considerably more over TES than with TpT. There are 0.6 million teachers in the UK and TES is an established and popular resource for them: offering a massive library of free resources, higher quality premium resources have seen many authors earn more than they take home as teachers! The ‘Premium Author’ option is relatively new for TES and so it’s a better site for new teachers to get started.
Teachers Pay Teachers (TpT) [Recommended]
TpT have somewhat cornered the market. Using TpT is an essential first step as an independent educational resource developer. The main downside to TpT is that it just has so many users that the competition is fierce and established authors tend to dominate: it’s a difficult market for new authors.
Teacher Lingo offers a setup similar to Teachers Pay Teachers (TpT). The basic membership is free and you will earn 65% of each sale. With a paid membership of $49 per year, your royalty bumps up to 85%. The site pays once per month via PayPal with a $20 minimum. This appears to be a small community, but they do offer forums and directories to connect with other educators.
There’s no cost to become a seller, so joining is risk-free! Educents only charge 15% as commission on products.