I wouldn't try to buy anything with a credit card while using Tor. Many online businesses, especially ones with high fraud risk like hosting companies, will reject your payment if you're using a proxy. The company I used to work for would suspend your account until you sent in a picture of a government issued photo ID. If you didn't within 48 hours, they would close the account and you'd have to wait five business days for the refund.
Bitcoin should be fine though.