There are many different levels of playing cards out there, but most people will end up just buying the cheap pack as an afterthought on their way out of the supermarket.
This is fine if you just want to be playing a few games with the kids, but if you intend to get a little more serious about your card playing, then you are going to want to get something a little more decent.
Of course, card games isn't the only card related activity that requires a decent pack of cards, if you are wanting to practice your slight of hand for magic tricks or (ahem) cheating at poker, then you are definitely going to want to spend a little bit of extra money on a decent set.
A deck of cheap playing cards can be really clunky and slippery to use properly, and the people who specialize in making them will be more likely to know what it is you are after than the cheap factories in China that just continuously churn this stuff out.
That said, you do not have to mortgage the house to get yourself a decent deck of cards, and just because you are after quality doesn't mean that you have to find some rare material that is impossible to get your hands on.
On the contrary, playing cards made from plastic can be every bit as professional as their cardboard counterparts.
In fact, if you go to just about any casino in the country, you will notice that just about all of them use plastic playing cards, even for their high end poker and blackjack tables.
These guys know what they are talking about, so if plastic playing cards are good enough for them, they will certainly be ample for your needs.