Ask HN: Is it worth to make promotions of your Apps?(XX% OFF sales)

A hackaton project of ours turned out to be pretty successful. It's an Android app which climbed the ranks quickly, now being in top 10 grossing in it's category in most countries, a month after launch.

Our app costs $9.99, and we're wondering if it would be worth putting it on sale (ex: $4.99 for a limited period). Two of us are already doing full-time support, and just doubling downloads for the same revenue wouldn't make sense.

In your experience, is it healthy to put your app on sale ?

Thank you!