I was just looking in the NES in the EVEPortal app, and out of curiosity, clicked on a skin, and then started clicking the +1 button on how many i want to buy, and i decided to stop clicking because i figured it would be easier just to post on the forums, than to keep clicking until it said “you have no reason to buy x amount of this one skin”
There is no hard limit. If you have extra of a SKIN, they can be sold on the market for ISK, if there is any player demand for it. For the record, though, you should not trust anything Eve related to throw up guard-rails to prevent you from doing something you’d have no sensible reason to do.
Unlikely there is. Why would CCP limit anyone spending their PLEX (which someone - the person spending it or someone else who sold it in-game - spent $$$ acquiring) in a limited fashion when people can spend it all (either willfully or accidentally)?
There definitely is a limit imposed by the computers themselves. I seriously doubt CCP would be using arbitrary precision variables for this and would go with unsigned int instead. The limit then would be probably 4,294,967,295.