in the original game, you can't buy ships yet(not in this version, probably not in Part I). Fortunately, there's mods that can be added to the game easily, and some (or one, I'm not sure), enable you to buy ships and even make an army. You can find most Transcendence mods at
http://www.xelerus.de. For buying and using multiple ships, I recommend PM's Player Drones. You need to update your Transcendence to the latest version to use most mods. You can find the latest version in this forum. Look in the Announcements part. To install mods, just unzip the mod folders into the Extensions folder in your Transcendence folder. Have fun!
Yes, look at my avatar, I have a wyvera type ship.