Big open ended question this...
Human nature dictates people will pay as little as possible, all 9.99 sounds better than 10.00 as most people say (to the wife) it cost me 9, not 10
But the big question is, what would they get for their money, you do not say what the subs are for. If its of value and interest to many people then it may work, if its specialised then it may not, or at least not for many people.
It is also true, reducing price sometimes gets you more in the long run, but again depending on the product.