How would you fix this cowl rust?

There are 2 budget ways to fix it. 1 is pick up some fiberglass fabric sheeting & some por 15 & once you clean out & vaccume the area out. Then cut the sheeting to sizes that you can mold into place. Then brush plenty of por 15 on the area,let it tac up a bit then apply the fiberglass sheeting to the area's & then apply the por in multiple layers until you are happy with it. It is mouldable until it starts drying up. I did this to a 67 a body years ago & it held up well & is water proof when dry. I highly recommend rubber gloves & 1 of those small black foam brushes so you can dip it in the por & reach over the lip in the cowl to coat that as well. It's about a $30 repair or you can find someone parting 1 out who can cut that area out for you then tac & weld it into place. It depends on how far you want to go & how much you want to pay