I take a view contrary to some posters here, not only am I happy to pay for a DLC, but I would also be happy to pay for Mods.
A mod is something that enhances my game experience, it provides me with more pleasure. Therefore, like the base game, it has a value to me and, like the base game, it has been created by someone using their talent and time. I would be quite happy to pay a contribution towards rewarding them for making something that gives me enjoyment. $2 for a mod doesn't seem excessive to me, I suggest that there are very few players who could not afford such a sum and the potential rewards to the creator would be sufficient (I see one of the mods I am using has nearly 33,000 subscribers) to encourage them to produce very high quality products in a very competitive market.
The price of a DLC is somewhat more ambiguous, is $12.99 a reasonable price. Well, that depends on how much extra pleasure one gets from it. If it provides at least 13 hours extra game play I'd say yes, without a doubt (good entertainment for a buck an hour, tops, is cheap). If its less time than that then more subjective factors come into play. However, the price is a marketing decision for the Company. What I don't think is reasonable is to expect people to give their time and talent for nothing and so a company must make money to pay their people.
A poster suggests that we deserve DLC for free. What have we done to deserve it? We paid a price for a product, which, for most of us, has given us a lot of very good and very cheap entertainment. So how do we "deserve" more for nothing?
I argue that 2 dollars is a bit much for many mods, and there would need to be a way to test them before buying. I think Modders should have a donation system, many people including me would donate a few bucks for the good mods. But, there is no way I'm paying 2 bucks a mod, I mean I used around 50 or so mods for Oblivion, 100 bucks for around the same amount of content as a good DLC? No, thanks.
I still disagree that we are entitled to free DLC, and we should be donating money to the good modders, though.