I like to think about it this way:
1) what is the highest price I could charge without looking like an idiot for charging too much?
2) what is the lowest price I could charge without looking like an idiot for charging too little?
Now I have a price interval.
If it's SaaS, I set the highest price for the shortest subscription period (ex., 1 month), and the lowest price for the longest subscription period (ex., 12 months), while adding additional options in-between (ex., 3 months, 6 months).
This way, I feel like both sides are getting a fair deal, and nobody loses.