Prices have already been adjusted to 750 for mini and 1250 for transport.
Just to address some of your comments.
will be the ones who have already reached endgame in a wip
The intent is to force mini copters to late mid-game / end game, this should hopefully make ground-based vehicles more appealing.
Alternatively, people might not buy them at all, because who wants to lose 1500/3000 scrap to a group of nakeds who boosted themselves to your roof to steal your heli.
This is part of the core problem with the current meta, players are not protecting their helis because they've invested little to no time and effort in acquiring them. Players should look at protecting their vehicles with garages or other forms of defence.