I suppose, new Xenonauts should have a Black market options, which allow player to make instant cash in exchange of future relation and/or reputation. That should be the place where you can buy or sell alien stuff, bribe a politician in the particular region (with some %% of success), hire the mercs to do your job on the crash site (with heavy civilian casualties). Also, it seems to me a good idea to add some black market missions, to trade you team as mercs - do some dirty job, like drugs or human trafficking in exchange of cash, rare materials or relations with particular region.
