I needed money so I thought I'd sell a planet and some corvette minions to raise cash. I got a fairly decent deal one time. I think it was my Arcean teamate who gave me about 3500 bc and 15000 influence points for Kona and 15 corvettes. The corvettes alone would cost 27000 so the deal made sense to me and the ships were less than a turn from the planet I gave him. It happened to have 5 billion people too. 

Things went wrong awhile later and I reloaded and I couldn't get a deal anywhere near this deal. I tried the same offer with the Arcean and several others and about the most anyone would give me for all that stuff was 33 billion credits and one influence point. I haven't been able to figure out why there was such a huge difference in the offers because I didn't lose diplomatic ability or anything. 

Playing as Drengin has been hard. I have no money. By the time I researched that thing that gets you the merchant symposium with the 50% earnings bonus, I can't afford anything. Maybe its because I'm so evil. I always check the evil box for the big bonus on the random event thing. I tried turning corvettes into constructors and better fighters but that proved to be expensive and no one wants to give me money for planets or ships. If I choose good options will people give me better deals? I leveled up my diplomacy a little but I'm Drengin and I don't have uber research skills. I thought I had to focus on improving weaponry and fighting and engines. 

I also thought that my many successes in battle would perhaps get me better deals because beings would look at me as this god-like creature, but that didn't work either. I whipped the terrans in a dozen battles and no one gives a whit, especially my ally who always greets me warmly. He won't hardly give me anything. I've given him gifts thinking that we're in this together. It makes no difference. 

I think the game is made for the Terrans and Alterians.