Okay, so it would cost X amount of dollars to see this sp. Think of that money as liquid cash for a moment. You have X amount of dollars in your pocket, think of what you can afford with that money. Do any of them outrank seeing this sp? if yes, spend the cash on that. If not, see the sp.
Just on a side note, how much have you built up this experience? The reason why I ask is, many people build up the experience SO MUCH in their minds, that when they finally take the plunge, they are deeply disappointed with the results. If you are realistic about what the session will be like, then you should be fine. If not, remember, you are dealing with a person, not a fantasy and what chance does she have in measuring up to that?