Never buy weapons in the Witcher 3

[Aerys]

The weapons to buy are only useful for those who rush the game, they dont discover ?, dont make a lot of side quest and dont look into every thing for interesting loot, so the game punish these one with overpriced weapons

 

I have a bigger problem : I'm too heavy, i dont know what to do, i sold every thing i could but i'm still at 130/160, too bad there is no 150kg bag