However, when you choose, you should first look at the qualifications of this company (mainly business license and SP certificate), and then talk about the price. At present, this is relatively transparent, generally at 3-6 points/article (less than 3 points is not recommended), and finally find a company that can provide free testing (see the rate and speed).
Buy a small amount at the beginning of the cooperation, and then consider a large amount of recharge when the cooperation effect is good. After all, it is a little province!