BibleStudy.tools logs basic information on attempts to access site resources. For example, date and time, requestor IP address, and requested resource are logged. None of this information is or will be sold. It's logged in case it's needed for forensic analysis in response to an attack on the site or resource exhaustion of the site.
If you create an account by using the Sign Up page then your account email address and username are stored. Your account password is never stored and can't be accessed by BibleStudy.tools personnel. Any information you save while you're logged in to your account, for example notes you take while reading the Bible, will be stored. None of your account information is or will be sold. It's kept and used to service your requests to access it and to enforce the site's terms of use.
If you visit the Payment Methods page under the Account menu and use one of the online payment methods, you interact with Stripe, an online payment processor. You don't leave this site to pay, but behind the scenes Stripe handles your card information and deals with your bank. BibleStudy.tools doesn't store and can't even see any of the sensitive card information you enter into the form that opens when you press the "Enter New Payment Method" button on the Payment Methods page; that form talks directly to the payment processor.
You can read Stripe's privacy policy to learn how they handle your information. It's quite long, but as you read it know that in there you're called the "end customer" and BibleStudy.tools is called the "business user." Keeping those terms in mind can help you focus on what matters for you and your use of BibleStudy.tools online payment methods.
BibleStudy.tools does have access to non-sensitive card information you enter online, for example the last four digits of a card number or a card expiration date. Other "offline" payment methods are also available that don't collect any sensitive card information. No payment information collected by or made available to BibleStudy.tools is or will be sold, and is kept and used only to process the payments and refunds that you authorize.
See the Payment Methods page under the Account menu for all the payment options.