I'm sure this has been done before (and probably proved nothing) but I was curious so I just did some sums based on what I paid for certain cosmetics pre-ARX and what they'd cost me now (AFTER prices are a range using conversions based on £24.99 ARX pack and £2.99 ARX pack).
Nav Beacon bobblehead (BEFORE: £3, AFTER £2.37 - £2.89)
Celeste COVAS (BEFORE: £5, AFTER £4.34 - £5.29)
Asp Raider ship kit (BEFORE: £8, AFTER £6.62 - £8.08)
Asp White Apollo paint (BEFORE: £1.50, AFTER £0.89 - £1.08)
I picked out these examples by going through my past orders and selecting, pretty much at random, items which I was able to find in the store now. From where I'm sitting it looks as if Frontier have tried pretty damn hard (harder than many on these forums deserve I would say) to keep prices the same or slightly cheaper than they were before.
And then on top of that they're also giving us free ARX just for playing the game so that three or four times a year even those who can't afford to buy an ARX pack can still pick up something from the store.
As for the why of ARX:
a) It gets rid of the per-transaction costs imposed on Frontier by credit card companies which previously meant the purchasing of very low cost items (e.g. an individual paintjob) be barely cost effective (hence why they used to favour selling paint packs rather than individual items).
b) It makes it easier and safer to bring the store inside the game since none of that code has to deal with real-world credit transactions.
c) It brings PC inline with the console model which makes life a lot simpler for Frontier.
d) It allows Frontier to give us cosmetic item earning potential within the game.
