I want to say that teir 2 ships are around 32.5k energy credits, the next teir was like 65k, and the final teir 125k. Those are ballpark numbers. I don't remember exactly how much they cost, It wasn't cheap, but by the time I hit LtCmdr I had about 15k, it didn't seem unreasonable. I wasn't farming the exchange or anything, that is basicly just selling the loot I can't use, and judging by how much ship components at higher levels cost, you should be able to buy a lower tier ship, say a T2 ship when you hit T3 without too much difficulty. I kinda wanted to have all the ship classes too, just to try out the various ones to see which ones I liked the best without having to grind a new character up. I hope that helps you out.