Yes you can buy the ships in SC outright but almost all ships (rare alien ships you have to capture) will be obtainable in game if you don't want to use real moneys.
If you hardcore game everyday then a Sub fee would be worth it. But as gamers get older, life and responsibilities get in the way. I maybe have about 5 hours in a week to do any gaming. And that depends if the weather outside sucks. Otherwise I'm outdoors or out and about. So a Sub fee to me is not worth it. I would be wasting my money.