Nope. They either last for a certain amount of time (~15-30min?) or a certain amount of missions (~1-2?).
I bought and used a couple, then went on a mission. I quit the game after the mission. When I came back, I no longer had the buffs from those items.
You still might want to buy them. The stats ones, at least, provide really strong buffs (7-8 points, not sure if it stacks), especially considering how low your base stats are (~10-18 at level 8).