Question 1:
Can I sell my champions?
Answer:
Yes you can.
If you were to go to the shop where you normally buy your champ and go to the tab "Purchases", you will have an overview of the last few purchases you made.
You should be able to find a "Refund" button somewhere (I dunno where precisely), which allows you to refund the champion which you do not like, in this case "Tryndamere"
Now, there are a few criteria that allow you to use this feature:
1. You must not have refunded 3 times before on this account
2. The refund can only be cast on something you bought within a certain time range, which I believe is ~ 3 months.
3. Really, you just can refund 3 times on 1 account.
4. Really, I mean, if you refund Tryndamere, Ashe and Nunu, then all your refunds are gone
5. They can be much better spend on bad choices you made, with higher prices. Like 6300IP or any RP price.
Do this, and Tryndamere will no longer be a problem
Question 2:
What is my opinion about Tryndamere?
Answer:
I hate him
:D