What's a simple, cheap treatment for my vaginal pain?

Vaginal pain. Vaginal pain can have many causes, and is best evaluated by your physician.
No simple answer. Unfortunately, we cannot provide you with a simple cheap answer without a diagnosis. I will suggest that the simplest, cheapest answer is to see a specialist who can make an accurate diagnosis and then apply the correct treatment. I see too many women that have had multiple incorrect treatments which costs time, frustration and money. Best wishes.
Find the cause. You need to find the cause of the vaginal pain before knowing what is the cheapest way to treat.