just started BT3 and am in the Tunnels.
my inventory explodes and I can't find any shop in Skara Brae.
is there a shop in the wilderness or when am I able to sell/buy ?

Unless it's been changed in the remaster and added somewhere, I don't remember there being any equipment shops in BT3. You'll find plenty of gold otherwise for all of the things you need it for, though.

are you serious ? no shop at all in the game ?

My memory might be faulty, but I don't remember there being any. There certainly weren't in Skara Brae. There might be some in one the other realms that I didn't visit very frequently, but I don't think so.

Same with review boards. There were only three in the game, I believe, so there are multiple realms where you cannot advance your characters. You need to head back to a dimension with a review board to level up, gain spells, etc.

There are no shops.

The remaster does allow you to store extra items in the stables near the entrance to Skara Brae.

Also, you can create extra characters and give them extra equipment, then just leave them in the refugee camp; this is another way to store excess items you want to keep. (Note that this method works best if you're using the legacy mode option that gives each character their own inventory.)

There are actually *4* places you can level up your characters in this game; the one in Skara Brae, and three places in the other dimensions (each of which has a shiny new spell for all your casters to learn).

(A good item to store in the stables, by the way, is the Harmonic Gem; if you run into a part of the game where Harmonic Gems aren't as common, this will reduce the need to go back and farm for more. They aren't that common in the endgame, for example (though in classic 8-bit versions they were *too* common in the two worlds before; this is probably where they reduced their appearance in the remaster; by *too* common I mean being able to NUKE every battle, using harmonic gems after each NUKE (instead of when SP gets low), and still getting them faster than I can use them.)