I think Jif makes individual tubs of PB, and they hold at least enough for thickly smearing PB on two slices of bread.

I have pre-PB'd tortilla wraps and they hold up well for several days.

But generally, I just get a small nalgene screw top jar or a small light-weight plastic container with lid and fill it with PB and use jelly packs or honey packs to add.