Eve Online isn't just a spreadsheet manager with a Science Fiction skin and a monthly fee. It is just different from Freelancer. It also offers much more freedom than Freelancer. I recommend you try Eve Online, they offer a free trial period last time I checked.

The singleplayer is mostly linear until you finish the campaign, then the world opens up. But several features were never properly implemented, so there's for example no variable pricing for commodities. The multiplayer just drops you on Planet Manhatten with the Starflier and some cash and you're free to do whatever.
There are however many mods and persistent online servers for the game, that adds a lot of content and features. There are few of these mods that have singleplayer versions unfortunately, and I could never be assed with the multiplayer because most of the servers have forced RP/larping, which I find to be very lame indeed.

I tried it.

I was not impressed. Far far too much number crunching. It was not a game I felt I could sit down and play for a half-hour.

Space Rangers 2 is a great choice, seeing as it's on sale.

I tried the demo today.it's a solid experience,but I'm having a hard time getting used to the physics

To name some games which wasn't mentioned so far:
Vega Strike
Deathwar 3030
Flatspace I + II

Many classics have already been mentioned,so for more recent stuff I would say X3 and Evochron Mercenary,both are really good,also keep an eye on the upcoming X-Rebirth.

I still play Frontier: Elite 2 on a regular basis.

Egosoft's X3:Reunion is quite fun.

I'll have to side with you, I'm afraid. The beginning seemed alright, but once you get to the point when the British fishmobile no longer cuts it everything goes to hell and the campaign gradually becomes a brutal meat grinder. I've heard the multiplayer is better, but if you want to play single-player only I would advise to steer clear of Freelancer.