Should I put the price in the ad?

If the price is a genuine advantage, or a useful filter that stops the wrong people clicking, yes. If it is ordinary for your market, use the promise instead.

How many versions should I write?

Enough to compare, changed one element at a time, so you learn which change did the work. Rewriting everything at once only tells you that something moved.

Clicks went up but sales did not. What happened?

Either the ad is attracting people who were never buyers, or the page is not delivering what the ad promised. Check the page first. It is the cheaper fix.