Right now, Porters I and II both require a Sapphire Necklace as input; this makes Porter I not worth using because the input cost is so high relative to the low XP cost to get to Porter II and its double charges.
In order to both make Porter I more worth crafting as well as giving low-level/FTP players a sense of value (ie. appreciate divination as one of many reasons to upgrade), I propose replacing Sapphire Necklace with Lapis Lazuli Ring. Why that specific item? Because it is the only low-level silver jewelry available to FTP players (Opal and Jade jewelry cannot be crafted by them.)
Reminder: Lapis Lazuli is mined in vast quantities from common gem nodes (eg in the Burnthorpe mining cave). In one minute's worth of mining, your backpack will have generous amounts of Lapis Lazuili after one minute of mining. This makes it readily accessible to low-level and FTP players before they reach gem-dropping mobs for higher-level Porters.