It's not obvious to me that this is necessarily a good place to advertise. Reddit's community is very fickle.
The projections for the ammount of money that will be spent [in/on] this little endeavor are astounding, to say the least.
For a cool new consumer product or service that makes money directly, though, this could be great. When I tried it, the CPC was very low. Whether it's worth it depends on how good a fit the thing you want to advertise is with the audience of Reddit.
I can't imagine making a great return selling something directly on there unless you product was so cool that a regular post would have had nearly the same effect.