For the past few weeks back I have received various offers through personal messages on this forum, asking me to rent out my signature, avatar, and personal text space...
In that case, you can be considered a very important person on the forum, because I personally have not received a single offer of a similar type in the past few weeks. However, every business offer should be considered, and every PM that may be suspicious can be reported to admins.
possibility of not getting paid since you are not under the management of any manager, or using an escrow.
You can be unpaid even if the offer is public, which is the case with some bounty campaigns that do not have funds in escrow. Risk always exists, and it's all about how much someone's reputation is worth, so if you agree to promote something for $20 a week, and it then turns into a scam, then it's your fault that you didn't refuse such an offer.
I'm not saying that payrate should always be the deciding factor, but I'd rather promote something I believe in for free than risk some cheap offer that could cost me my reputation at any moment.