What Materials Can You Print Onto Using The Silk-Screen Method?
I Know You Can Print Onto Cotton Shirts. But What About Polo Shirts? And What Others? Is There A Material It Won'T Print On?

You can silk screen on just about any material. Including polo shirts.

Fundraiser T Shirts (Not Sure What To Do)?
Im Printing Fundraiser T Shirts For A Friend Who Is Sick, I Never Done This Before. Should I Deduct My Cost From The Total Money The Shirts Are Sold For? I'M Not Well Off And Struggling Like The Rest Of The World. Example: If The T Shirts Sale For $12.00 And I Deduct $4.00 For The Cost Of The T-Shirt (Im Not Charging Setup, Labor) Would That Be Ok? Also I Do This Out Of My House.

Are you screen printing or iron on transfers Just deduct the cost of your materials ( t-shirts,inks, chemicals etc.)
screen print
t-shirt $3.
ink print $1.
screen set up $2.

transfer print
t-shirt $3.
inkjet print ink and paper $1.