- Trade via staking - find a trustworthy buyer with a higher-level account. You can put a deposit down with them and stake vs their gold until you lose. This way it looks like a legit stake rather than a straight trade to a level 3 F2P mule.
- Use a mule on a VPS. Make sure the mule is created on a different IP to your main account as well as played on a different one.
Depending on what the amount is, you can get away with straight trades a lot of the time tbh. I've personally never been banned and have RWT'd several billion GP on both 07 and RS3. I've used accounts ranging from fresh off tutorial island to a 2200+ total level (07) acc back when it was top 400 on the hiscores.