It's becoming difficult to find military vehicles in the toy cars section lately, but there's a new arrival at the Dollar Tree chain in the U.S.:
The range is named Military Playset, and each pack contains two toys for the $1 USD price. Made in China, they are imported by Greenbrier International in the U.S., and DTSC Imports in Canada.
I've spotted three packs in the series so far, comprising six models, in 'whatever fits the packaging' scale.
The boat is entirely plastic, with no crew figures and no moveable parts. For gaming purposes, you would either need to cut the bottom hull off or base it on a 'watery' base. There's a seat in front of an instrument/radar panel, and various stuff on deck but no obvious weapons. The seat is 4mm square, to give you an idea of scale.
The 'army car' has a diecast green metal upper, with transparent plastic (windows), white plastic (interior), and black plastic (bottom/bumpers), plus wheels (plastic with prominent seam). No driver, no steering wheel. The metal top part clips into the bottom plastic part.
The tank has a diecast metal upper hull, black plastic lower hull, green translucent plastic turret (no bottom), with toy wheels hidden between the treads. Turret rotates; gun does not elevate. Riveted body.
The self-propelled anti-aircraft gun has the same hull as the tank – right down to the decals – the only difference being the turret. Guns elevate in unison; turret rotates.
The rocket launcher truck has a diecast metal cab, green plastic rear hull and rocket, clear plastic windows and lights, black plastic lower hull, and plastic wheels. Held together by screws. Rocket rotates and elevates. (Rocket is one piece with launching rails.)
Lastly, there's a tank – no, really, just a tank. Could work as an objective or hazard.