Can't you transfer it to a different reseller in the first year? You should be able to switch resellers with your domain. In worst case, you can start your own reseller.
I don't understand why it would be 500 euros/year. Once you bought it, it's yours, you can renew it for 9/year.
Believe me I hammered their registrar the day the domain expired, looking to purchase it. Of course it then went into a redemption-state. But eventually, it became mine. Thankfully the previous-owner was willing to let it go.
(Sorry.)