Is trading in virtual weapon skins within a video game, by buying them at a low price and selling them at a higher price due to increased demand, permissible or forbidden, especially considering that the origin of some of these skins may be from "loot boxes"? If it is forbidden, is it permissible to benefit from the money earned from it or to use it to pay for games and movies that were previously acquired through illicit means?

There is no objection to spending money on electronic games to obtain new tools or upgrade the game, provided that the game is permissible according to Sharia (definition). Earning money from these games is permissible if the game is free from Sharia prohibitions. The basic principle in dealing with the tools obtained by players is soundness, and there is no harm in buying tools from them unless it is known that they were acquired through illegitimate means.