This involves the agency fees of trademark offices or lawyers' fees. At present, the agency fees in the market are generally higher than those in 7 yuan, that is, the overall cost of registering a trademark has to start from 1 yuan. Of course, it doesn't rule out that some people charge lower fees, and it's not impossible for 6 yuan to pay the overall fee. However, based on his six or seven years' experience, it's difficult for 6 yuan to entrust reliable professionals with the fees.
There are many Internet-based agencies that even provide free registration, that is, they only charge the 3 yuan Trademark Office, and no agency fees. You can search for "free trademark registration" on Baidu to find out.