well,...............beating the sh*t out of them, i will do that for sure !!!!!!
but as for cost......mine was free, (recycled electric motor covers) so no cost to me,
i had to use a press to bend what i just did, a-arm gaurds and my style air scoops, < check my recent build thread for pics
add some heat with a propane torch too or most aluminum will crack when bending, or soon after
it's tough stuff,