Probably, you can see a lot of similar services in the Services Section, I don't see it as illegal as long as they provide the subscription to the buyer, it's fine. It's her/his business, we should check the credibility of his/her service rather than having doubts and questioning someone based on the price.
Bumping a thread is normal especially when someone is having a business, I don't it's considered as spamming, just follow the rule of bumping once per 24 hrs.