Hero A is out of stamina
Hero B has a bottle of stamina from a search card

If hero A moves past hero B and use a free action to receive the Stamina potion (item?), can player A then drink the potion immediately and gain full stamina and use that for skills/extra move and so on?
Or does he have to equip the item in the next epuip item fase?
I'm not sure whether that rule goes for search card items. It doesn't say on the card that you need to use an action to use the bottle.

As I read the rules it looks as if you have to equip search card items the same way as other items.
That wound also mean that you can't find a potion and drink it on the same turn either.

Have any of you an answer to this?

Rules say about:

Trading Items
Heroes may give or receive Shop Item cards, Relic cards, and Search
cards to or from each other during a move action. At any point during
his move action, a hero may trade any number of Shop Item cards, Relic
cards, or Search cards with an adjacent hero . Trading does not require an
additional action or the expense of movement points.

A hero must still wait to equip any cards he receives until the start of
his next turn . Heroes cannot trade Class cards (including their starting
equipment) with each other. A hero may give another hero a card without
receiving one in return; likewise, a hero may receive a card without giving
one in return.

Yes, Hero A can use a move action to get the potion from Hero B and then immediately use it. The only items that need to be equipped are the ones with icons at the bottom, such as the hands. Everything else such as potions goes into a catch all bag of sorts that you can just draw from as needed.

EDIT: Source if you wanted a more official answer

Thx for your answer and link ProtoPersona