Currently, the 1c1g VPS is out of stock, so you can’t get one for a whole free month with 20 RMB. If you pay by usage per hour, you can only use it for 10 days, and you can’t use the 30% off coupon.
You can use a custom config to change the default 1 month to 0.75 months. Note that you need to copy and paste 0.75 in.
This is a scam for affiliate (aff). When you go through the link, it says you’ve registered before. Forget it—can’t play this game, probably going out of business soon anyway!