Should I check IP blacklist when buying a shared hosting? I think i can face any risks when buy a shared hosting plan because on shared more users are using a same IP address which can get blacklisted whenever?
The host is responsible for providing the IP, which is clean at the time of the purchase. If you have a concern that it may be blacklisted it is best to check it after purchasing and ask to change it if it is in a blacklist or get a refund for it.
It is in the eeb hosting providers best interest to run SPAM free and blacklist free services and to make sure that their IP addresses aren't blacklisted. Still, it does not hurt to check any IP address against blacklists. However, you will not know the IP address of the server or the dedicated IP address (if you buy one) that you are going to use, before you sign up.