Ehm, "Free"lancer is anything but. It's just as linear as a WCP with mini side-quests. The freedom you're given, to go out exploring, or to haul cargo or take on missions to make some money, or to work on your reputation with the various factions.... all that is made absolutely inconsequential or is severely restricted by the terribly poorly developed storyline.
- As Chris said, you're almost never short on money. When you are, you are short not to upgrade your ship to fight tougher bad guys, but to reach the next artificial and absolutely meaningless treshold the game imposes upon you ("You must earn another 10,000 credits to, erm, advance to level 10.")... And even in those cases, you usually only need to make one or two profitable cargo runs, or two or three missions.
- It takes too much killing for someone to hate you, in a way that it's nearly impossible, after doing the initial missions, to get the "bad guys" to like you at any point earlier than when they actually get turned into the "good guys" by the linear story. And in some missions that doesn't even matter, because even if you "grind" your reputation with a faction so that they are now friends with you, they might be scripted to kill you on your next story-related sortie. Heck, from the very first mission in the game, you are already forced to work for a specific faction, ruining your reputation with a lot of other guys, and you are not given the option to simply say "screw this, I'm done with helping the navy kill pirates" (because you are restricted to one star system until you advance the story enough). So, you have absolutely no reason to work on your reputation with anyone - just wait and the story will do it for you. If you do it on your own, you're likely to find that you can't currently buy anything from that faction anyway, or that they're scripted to turn into enemies soon.
- Even if for some reason you made a huge fortune, and got on good terms with the factions of your liking, you'd still not be able to buy all the best stuff, because the universe isn't fully open at any time. You are always restricted to certain portions of space, either by being denied access to certain jump gates, or by having a scripted event in the linear storyline make everyone in a certain area suddenly want to kill you. So, you have absolutely no reason to save money, just play the storyline until you find yourself in the system that has the equipment you want to buy.
- As those areas open up, the single most disappointing aspect in the whole game becomes evident (as others have already pointed out) - each system that opens up is "harder" than the previous ones, with "higher level" gear and better ships available - even though it might not make any sense from a in-universe perspective that a bunch of random pirates in sector Psi-Tango-33 have light fighters that are better equipped than the mighty Liberty Navy Battleships from the first system in the game. So, you have absolutely no reason to go back to previously visited systems... just always keep upgrading to whatever it is they're selling in the last system the storyline took you to. But hey, if you hang on for another mission, the next system has even better stuff, so just don't bother upgrading either, unless you absolutely have to.
- The storyline cheats all the time. It uses a cheap plot twist every other mission. When you run into your first battleship, your underarmed light fighter is just enough to take it down. When you run into your tenth battleship, your overpowered ultra heavy fighter is just barely enough to take it down. Nevermind that both battleships were supposed to be the same class. When you have to destroy a station for a mission, it spawns a station for you to destroy, in a place where you knew there was nothing just a minute before, and you will find out that you can't destroy any other stations that are exactly like that one but which were not spawned specifically for you to destroy (how is that an improvement over not being able to destroy any stations at all?). You are now friends with pirates? Great, now you can buy all the drugs you want, which sell for a huge profit in police-patrolled planets - oh, wait. It did sell for a huge profit in those police-patrolled planets that you can't go to anymore now that you're friends with pirates. For some reason, illegal narcotics are actually cheaper in the police-patrolled planets that you can now visit than they were in the pirate bases you bought them from, which are listed in the navmap as great places to buy it!
Damn, I get all worked up when someone says anything good about that game. Come up with a dozen colorful nebulas and combine WCP's mouse-flight with semi-turreted guns, and your subpar game is now magically considered "pretty" and "fun".