GC's (and the subs they work with) are who put together the budget for what the costs would be to build the things you described in your budget. 

They can make or break your renovation budget.

I find saying you're doing it to "learn" is better received then "i'm doing it to save on costs" since they may get the feeling you're going to micromanage them and scrutinize the budget.

Look at property values, trends, and neighborhoods to identify opportunities.5) Create a Budget: Determine how much you can invest, considering all associated costs like down payments, closing costs, and maintenance.6) Build a Network: Connect with real estate agents, investors, lenders, and other professionals.

Eliminate debt, establish a budget, and save.

The low budget approach to be taught by experts.Have you read books on flipping?  

Doing a lot of research is critical, too—understanding the local market, the laws, and the best neighborhoods for your budget.

2) When using other people's money to invest, what is the best way to set up an agreement on a limited budget?

I once found a wedding cake on the kitchen counter with ants crawling over it. 

Quote from @Chris Seveney: @Jay HinrichsHey now :) (haha we have 700 investors)It can be done but you need a dedicated person to do it and make sure you budget for it - spending all your time raising $ for other deals and on the podcast circuit takes away focus.