Selling keys at Steam market

So, I have some games for trade. Overall some peps wanted to give me those keys or smth for the games. I'm not intrested in such stuff...well, I wasnt till now

The question is - If I will receive such key as a steam item, will I be able to sell it on market ? Or do I need to be a lets say TF2 player with premium account (or whatever its called in TF2) in order to be able to sell those keys on market ?

I'm asking cus if I dont need to have any prem acc or dont even need to play the TF2, then I could exchange some of my titles for few keys, sell it on market and buy some games with the steam wallet cash that I will get from the keys (I think I could get smth like 18-20 keys for all my leftover games and this is around 35 euro after selling them at the market :) )

The separate question is - is anyone actually buying those keys at steam market ?