My dad picked one of these up a few weeks ago and we’ve used it for just about everything – cutting drywall, laminate, nails, tile grout.  It was awesome for undercutting the door jambs – put a bit of scrap flooring under the blade and go right in. Rockwell RK5101K Sonicrafter 37-Piece kit

Replacement blades that you’ll use the most of: Rockwell RW9122.3 Sonicrafter 1-3/8-Inch Universal End Cut Blade, 3-Piece
One of those will last you a good while.  One blade has done at least a dozen door jambs, lots of drywall, a couple nails (inadvertently) and a few plunge cuts through some pretty hard laminate.