Here's a comprehensive set that features flatblade, phillips head and pozidrive screwdrivers, it also features stubby screwdrivers for use when a long handled screwdriver cant be used due to an obstruction.
If you don't mind spending a few quid you can't go past Stahlwille for quality.
Now a lot of people mistake pozidrive screws for phillips head screws and use a phillips head screwdriver on a pozidrive screw. Here's the difference.
O the left side is the phillips head screw and driver tip and on the right is the pozidrive screw and driver. You should notice the head on the pozidrive screw has tiny additional slots these correspond with the small additional blade on the tip of the pozidrive screwdriver. Those extra slots and blades help center and grip the screw.
Now you my well think it wont matter if you use a phillips head screwdriver on a pozidrive screw but the problem is the nearest size phillips head driver isn't a good fit in the pozidrive screw and you risk chewing the head out.
So look close next time your working on the car and you'll see it's full of pozidrive screws and use the right tool for the job.
The most common sizes of pozidrive screwdriver that you'll need is #2 & #1 those two sizes would probably cover 80% of pozidrive screws you'll encounter.