The reason squires charge higher prices is due to not only the cost of buying the items to do the repair skill in the first place but the 50% tax that is applied to any time the skill is used by another player.
The repair item costs 80 silver. Each item requires 1 repair stone per star plus another stone per rarity(blue is one, purple 2, etc). So a 3 star, blue item would require 4 stones. That’s 320 silver to start. Now there is a 50% tax on EVERYTHING we earn so in order to even break even we would have to charge 640 silver. That’s just to break even. Keeping in mind we are trading 2-3 class ranks, 100+ levels and all of the time when the shop is up as we are locked in place in exchange for making a profit and then you start to see why we would like to at least make SOME profit. So if I say charge a very modest fee of 900 silver(this is very low compared to some shops) to repair that item. 50% of that is taken off the top leaving me with 450 which then after removing the 320 for repair materials I am left with a amazing 130 silver.
I traded a lot of time and energy for a set of skills that is hard to justify even being worth using in the first place. So why should you use the squire to repair? Because time is money… The time spent, running from an instance to a warp statue, paying the cost to warp there, repairing, running back to the statue, warping back, running back to the instance hub and then jumping back in queue can be a huge pain. Lets not talk about how people never figure in the cost of the teleport into their repair costs.
Your paying for convenience. You save time and with the bump in repair value you will have longer before you HAVE to be bothered dealing with that same problem again. Its why you take your car to the store instead of walking. It costs more but at some point its just worth the extra cost to not deal with the hassle.
I hope that helps. Personally I think a lot of people are going to go squire and regret it when they see just how little you make and how much you have to give up for it. I think your going to see a lot of players retire their squire to a lifeless shop not to long after picking the class. At least at this point, its not a good class.