some questions about wholesaling

[Matt Faller]

Okay, I've heard that wholesaling can be done two ways,
1-
Get the property under contract, then charge the buyer an "assignment fee" for the property under a separate contract.

2-
Get the property under contract for (example $10,000), then, raise the price as you see fit with leaving profits for the buyer (i raise it to $15,000) and sell it to an investor and your price, leaving you the 5,000 difference at closing.

Which is more commonly used?
Ive heard it done both ways, personally, I'd prefer the second option, but is that something regularly done?
Thanks.