I think Valve is wrong making this decision. I'll try to make a point: 1) It's wrong to introduce paid mods into a consolidated modding environment like TES V one because it may likely cause an important loss of balance in the modding scene of the game. 2) It's wrong to give such an unfair slice of the cake to the content creator because he'll probably be obliged to charge an higher price in order to make a decent income. 3) It's wrong the refunding system because 24 hours is a too little amount of time to completely understand the goodness of a mod (I'm thinking about the bigger ones particularly). 4) It's wrong to put a price tag because it's pretty discouraging for people to buy before trying something like a mod. My solution? A donate button for every mod and Valve takes a really small percentage to cover storage/bandwidth costs (5 to 10% of any donation may be fair enough); nothing for the developers and the publishers, they already benefit from the presence of the mods as an incentive for new people to buy their game.