I have trouble with learning what pieces to sacrifice when. Any good examples or playable scenarios on the web to help guide with that? My biggest problem is in the early game, learning what to sacrifice to move pawns out of play so I can move other pieces up the board. Any assistance would be appreciated.
A sacrifice made at the beginning, with no clear and immediate advantage, is called a gambit.
There is no hard "rule" for when a gambit is worthwhile or not; it all comes down to what imbalances it gives you, and whether you think you can use those to your advantage.
For example, in the Danish Gambit (accepted), white sacrifices two pawns, hoping the extra space/development he gains will help mount an early attack. In the Queen's Gambit (accepted), on the other hand, white sacrifices the pawn knowing he will either get it back, or black will have to severely weaken his position to hold onto it.
I look at a sacrifice as an "exchange in disguise."
For example, you have a (castled) rook on the open f file, which you "sacrifice" for the knight on f6. Technically it's a sacrifice of 5 for 3. But maybe that knight is a key defender and Black is helpless without it. Also, if the rook is recaptured by the g pawn, that alone, is worth the sacrifice, because you've removed the f knight AND g pawn (now doubled on the f file) for "only" the rook.