If you're going to be storing customer information, get yourself at least a
VPS. Keeping sensitive information on a shared host is too risky in the long run -- you're relying on the fact that the admin of the virtual host is concerned about security. I have seen a couple shared hosts where I could run select queries against other people's databases and if I wanted to be malicious I could have walked away with thousands of records of peoples information. Also have seen a bunch of shared hosts with a ton of exploits/injections.