On pricing subscription products:
If you have recurring billing, there can be a big advantage to making the price really low. If its low enough and people stop using the service, they are often likely to (1) forget that they ever subscribed and (2) not think its worth their time to take the time to cancel.
For example, say you get a monthly recurring charge of $3.88 or $4.72 or even $2.68. It might be low enough that they don't even bother ever canceling. Not worth the bother.
If that is too low to support your costs, you usually want to go two above or two below the nearest factor of 10. For example, 8 or 12 or 18 or 22 or 48 or 52.
Also, its best to price products with even numbers. Even numbers are 'softer' and more 'friendly'. Two or eights are 'nice'.
Finally, if you have something on auto recurring billing. The holy grail is to have people forget about the charge and not think its worth their time to figure out how to cancel. You have to determine what that 'I don't care' level is for your customers. For some its below $50, for others, below $20, and others below $5.
Another thing that helps with this is to go with cents in the charge. For example, 2.68 versus 3.00. If its 2.68, it looks like it was taxed upwards and looks more legitimate. If it was an even number, like 3.00, it looks very deliberate, something that wasn't taxed, and is and worthy of investigation.
(I used to study this stuff when I was a VP of Marketing)