We also share those same concerns. That's why rather than having our own private payment processing portal we elected to let PayPal handle all of our Transactions.
Why? PayPal 100% Protects BUYERS & SELLERS from FRAUD & SCAMS. Also, your sensitive financial information isn't shared with us.
CHECK OUT THIS VIDEO:
If you are still nervous about using your primary card(s) then think about picking up a PRE-PAID card. Using pre-paid cards are a way to engage with online merchants to build up trust before using your primary card(s). Some folks exclusively use PRE-PAID card for internet $$$ engagements.