Other grant courses cost a lot of money--I've seen prices as high as $1,499.00, which doesn't include other costs, such as airfare, hotel charges, and restaurant bills. The least expensive reputable course, that only covers foundation grants, sets you back $595.00, for 2 days of information and 1 day of practice--and again ignores the real costs of travel.
You won't know much about the presenters, either. They may have just been given a script to follow, without every having had to prove themselves in the real world of writing grants.
And don't forget the hidden price you pay--time away from your office, your family, your LIFE!