This may vary depending on the game. Let me make a list:
Game 1: f2p, cant use robux to get ingame advantages
Game 2: f2p, cant use robux to get ingame advantages
Game 3: paid access, cant use robux to get ingame advantages
Game 4: paid access, cant use robux to get ingame advantages
Game 5: f2p, able use robux for ingame advantages
Game 6: f2p, able use robux for ingame advantages
Trade A: Game 1 to Game 2
Trade B: Game 1/2 to Game 3/4
Trade C: Game 3 to Game 4
Trade D: Game 3/4 to Game 5/6
Trade E: Game 5 ​to Game 6
Trade F: Game 5/6 to game 1/2
Answer in this format (example):
Trade A: no
Trade B: no
Trade C: no
Trade D: no
Trade E: yes
Trade F: yes
Cross trading of any kind which include Robux, real life money, or items from different games is not allowed and is definitely bannable. People shouldn’t even be doing them in the first place since you could easily get scammed since they are trust trades.
Do not sell, trade or give away Roblox currency, digital goods or game codes outside of the channels provided to the users on the Roblox site.
Do not permit or enable the selling or trading of random virtual items obtained in your game(s) or experience(s), for Robux, real currency or anything of value off the Roblox platform.