You can hit the Healing Springs every half hour to heal your pets if they take damage in the Battledome or have a random event or SHH / Something Has Happened event that knocks down their hit points. You can also opt to buy the healing potions there but you are limited to one per visit and can only purchase once every half hour. There have been times when I have not been able to buy them every half hour so don’t count on it being available every time you go there if you are visiting on a schedule. You can get all of the regular healing potions from Healing Potion I (35NP) through Healing Potion XII (32NP). They all have different healing rates to them and before the Battledome started giving out tons of prizes most of the potions were extremely cheap.
Even if your pet is at full hit points and health you can still visit the Healing Springs; there is no guarantee that your pet is going to get healed every time you go there. You might only increase 15 points but there is a chance that you can get a healing potion or snowball. The snowballs are not for healing but you can resell them for a couple of points. The snowballs that you can get there include Icy Snowball (5NP), Peach Snowball (25NP), Exploding Snowball (10NP), Wet Snowball (25NP) and Poison Snowball (100NP). Buying them is not recommended because most of these can be found for a couple of points on the Show Wizard.
The best selling potions are the Super Strength Healing Potion (225NP), Dewberry Reviver (175NP), Essences of Everlasting Apple (250NP and Bubbling Healing Goo (200NP). These are currently selling for anywhere from 500NP to 900NP depending on the demand for them. That can mean a nice little profit from them if you buy a couple every day when you are online. With a pending plot and the chance of it involving battling you might want to start stockpiling these because the prices will go up even higher than that. Any of the higher number healing potions can easily be resold for profit but you need to check the Shop Wizard to see what is in the most demand when you are pricing them.
The Healing Springs can cure a pet of anything so before you start buying expensive cures for some of the diseases you should visit that part of the site a couple times to see if you can get a complete heal. If you pop on a couple times a day to grab a scratchcard or do the dailies just add that to your list so you don’t forget. Normally I wait until I have 10 to 20 of a certain healing potion before I list them in my shop but there I don’t stock them all the time. If there is a plot or war then you want to be prepared for yourself and for reselling. You aren’t going to want to pay 600NP for something that you could have snagged cheap so don’t sell all the potions you have or you will have to spend your profits buying them for yourself.
I had over 600 Healing Springs Residue that I bought when they were selling for 5 to 10NP; when the Battledome reopened in beta and everyone has access to it I started selling them for 400NP (a huge profit) and would sell out in a matter of minutes. The price has dropped significantly but it’s rare that you see them for less than 100NP. That’s just one example of how hoarding can really pay off in the long run; that’s no guarantee that every item you stockpile is going to skyrocket but it’s not like you are forking out a ton of NP to buy them when they are selling cheap.