Half the time I visit Lowe’s it’s to buy something for my home. The other half of the time… it’s to buy something for training golfers.
That said, the single best item is a $2.99 “driveway marker” stick. Orange or yellow, most often, and sometimes with a metal cap and/or reflective tape, these are found in several aisles but often near the mailboxes. 🙂
Alignment sticks can be used to do so much, including acting as an alignment aid when you are practicing every time. The single best drill for many may be to put the alignment stick in the ground, in front of you, on the target line, angled at about the same angle as the shaft plane. Forcing players to swing OVER the stick will often cure them of swinging left, producing pulls and slices.
That said there are a LOT of other uses for an alignment stick. Or a driveway marker.