I love pies because of  they contains a filling of various sweet or savoury ingredients.
I do love pies but am not a baker so not sure what all goes in to making one. Would you happen to have any tips?
Yes, the crust matters alot. This is because Pies are defined by their crusts
I can see that. Are there different types of crust for different pies?
Before i answer you, let me give you a big clue, the filling is placed on top of the pastry but left open 
Well, I was asking because I thought I had heard before that there were different types of crust that could be used. Such as graham cracker crust, etc. Is that correct?
I'm not too sure but i know there is a top crust and a two crust pie  filling completely enclosed in the pastry shell.
Well, that is good info to know. I know there are blackberry pies, apple pies, pecan pies, etc. Do you know of any unique pies that some may not know about?
a pastry or other covering before baking. A "two-crust" pie has the filling completely enclosed in the pastry shell. Shortcrust pastry is a typical kind of pastry used for pie crusts, but many things can be used, including baking powder biscuits, mashed potatoes, and crumbs.
Pies can be a variety of sizes, ranging from bite-size to ones designed for multiple servings.
History.
The need for nutritious, easy-to-store, easy-to-carry, and long
Pie
A pie is a baked dish which is usually made of a pastry dough casing that covers or completely contains a filling of various sweet or savoury ingredients.
Pies are defined by their crusts. A "filled" pie (also "single-crust" or "bottom-crust"), has pastry lining the baking dish, and the filling is placed on top of the pastry but left open. A "top-crust" pie has the filling in the bottom of the dish and is covered with