Thanks for your post. Your listings are currently submitted to us by tourfactory.com and www.realtyxonline.com. You should make sure to update your listing prices on these sites (tourfactory.com uses a data feed, make sure the feed gets updated as well). Once Trulia receives the updated information, your listings should update within 24 to 48 hours.
For your information, only manually submitted listings are completely editable on site at the moment. Some information, like open house times and photos are currently editable, and we are actively working on making other information editable, such as prices, as well.
Sol with Trulia