Assignment fee or percentage of asking price? What's better?

[Mikey Cas]

Hi everyone. I have a few questions about wholesaling. I found a property could potentially be an excellent deal.

1. When marketing property to potential investors after i tie it up in contract, do I include the assignment fee in the selling price, OR for example I have the property tied up for $300k and list it at $350k as a starting point and lets say we negotiate down to $310k...The extra 10k is my profit? Or is it a separate fee?
2. When listing the ARV, I have done some comps on my own looking up recently sold homes. Should I pay for an appraisal to get a rock solid number?
3.In the beginning Do I tell the seller my intentions of flipping it to another buyer? Will this make buyer suspicious or less willing to work with me as a newbie? I have spoke to some people already and they have no idea about wholesaling etc. So I don't want the seller to brush me off. And to keep costs down can I not involve an attorney? I would like to use as little money as possible for my first deal.

Thanks for your help guys!!!