Check to see if you have smart pricing turned on. It will automatically change the price based on market demand. If you are concerned about it going too low, you can set a minimum price. Smart pricing cannot go below that number. You also need to see if you have discounts turned on. It was defalted to on for me when I started hosting and I lost a bunch of money on my first booking as a result. You can turn discounts off or edit them to give a certain percent discount for various lengths of stay. As for the difference in price between hosts and guests, the price guest see includes fees/taxes that are not paid to the host. For example, my minimum price is $70/night, but my guests see $79/night because there is $9 in taxes they have to pay for each night on top of my $70 rate.