First of all, welcome to the game! Always nice to see new faces, and I hope you're enjoying it so far!
As far as money making classes go, you have multiple options, but Pardoners are definitely among the more well-known/frequently used shop classes. One of the most popular Pardoner builds is Cleric2>Priest3>Chaplain>Pardoner2. Depending on how soon you want to be making silver, you'd either go Pardoner2 (rank 6 & 7), or chaplain right after Priest 3 (rank 6, then Pardoner2 at rank 7 & 8. People take Cleric2 in favor over Pardoner3, since more points into Pardoner's buffs doesn't offer a whole lot). This is a full support build, which means SPR investment should be quite heavy (or even Full SPR), and combat will be a bit tougher. But in exchange for what you lack in combat, you become very useful and profitable.
The Spell Shop skill for Pardoner2 is where you sell your Priest's main buffs: Aspersion, Blessing, and Sacrament. This is what Pardoners are most commonly associated with, and easily one of the more profitable options at their disposal. Spell Shop is the bread and butter of any AFK Shop Pardoner, but you can also sell scrolls of your skills crafted through Simony on the market, usually for more silver depending on the skill scrolls you sell.
Here's a list of all the skills Pardoner can turn into scrolls, and the classes to which they belong:
Cleric: Cure, Deprotected Zone
Krivis: Aukuras, Zalciai, Daino
Paladin: Restoration, Turn Undead, Barrier (Paladin3)
Oracle: Arcane Energy, Clairvoyance, Forecast
(NOTE: I may be missing a few)
Outside of Pardoner, there are quite a few other money-making classes, within different base class branches. Squire repairs gear, and enhances Armor and Weapons (most Squires typically focus on one of the three). Enchanter... enchants armor, as well as turning various wizard skills into scrolls (Though given that it's a rank 8 class, I'd recommend against going for it if you're looking for quicker income). Appraiser identifies items found in Hunting Grounds (it's a rather hard-to-get hidden class, and takes a lot of time and patience to acquire). Alchemist crafts potions and removes negative effects on Gems, as well as other things.
Despite the wall of text I've provided, I am by no means an expert on ANY of the Shop classes, and am only informing you of trends and rationale that have come from Pardoners I have met in my time playing the game. I'd say your best bet for more in-depth info is finding an active Pardoner in game (or in your guild, if you're in one) and getting tips from them.
Good luck, and once again, welcome to Tree of Savior!