Hey guys I saw yesterday that i have some money left on my PSN Account so I started thinking about buying one of those PSN games. But I never bought one of those can you suggest a few titles.

The only PSN title I know is Malicious it looks pretty interesting, if somebody knows it maybe (s)he could me bit it if its any good.

Wait for Journey :)

or buy 'The Last Guy' its fantastic

I suggest you take a look at Flower...

You should know by now that PSN has no games, so no idea why you are asking this.

everyone is going gaga for Journey but that's not till a week or 2 for now.

I'm a sucker for
Numblast,
flOwer,
Super Sonic Rocket Powered Battle Cars (I wish I was kidding but that is its actually name)
Elemental Monster Card Battle
Cubixx HD
The Last Guy
Echochrome and its many iterations
SuperStardust
1000claws
Dracula Undead Awakening
Sodium: Salt Shooter (Okay, this one isn't technically PSN as it's on Home but still...)
EA's Tetris
Auditorium
Hustle Kings
Critter Crunch
Wipeout HD/Fury
Flight Control HD
Tumble
Back To The Future episodes 1-5
Comet Crash
Dead nation
Pixel Junk Monsters
Pixel Junk SideScrollers
Shatter
Under Seige

To name a few...

Fat Princess no doubt.

PixelJunk Shooter too. Awesome game.

I forgot.. if you like twin stick shooters give Super Star Dust HD a try. I love that one!

If you like twin sticks, you need to mention 
Riff: Everyday Shooter
Soldner X:
Soldner X 2

As an aside:

Calling all Cars
Orbit

I don't know that one. I'll try it tomorrow.. Thanks !

Here's some random reviewing it, I don't think there's a demo I can't remember where I found the demo.