In any case that could be good price for the domain name registration only (first year), next year you may have much higher price.
I have to agree with you. Most cheap domain registrars use this strategy to get the money out of the clients, but hey it is easy to avoid them. If they are ICANN accredited registrar (and usually nobody registers on a non-ICANN registrar) they should state the price of the domain renewal somewhere (TOS, shop, prices page, etc.) and the users simply transfer the domain to another (and trusted) domain registar, however (as the topic starter) said, they don't charge more for domain renewal and this is more than fair.
As you see more than 80% of the people said that the prices are very cheap, but as you know you can't big the big registrars in price, I would rather recommend you to make something special and stay off the crowd, this is the only way to succeed if the competition is big.
I hope you success with the site, and if I see that you grow you may see me on the site.
Best regards,
Zolesz