Price cap on anonymous purchases

My go to options for private purchases has been IronVest and pre paid credit cards. I needed to purchase an item that was $475 plus tax. The tax pushed this purchase over $500. This is the limit with IronVest and with any cards I have purchased.
My threat with this purchase was low. My main concern with using a major credit card is just credit card fraud.
I decided to use PayPal which already is set up with a major credit card. Time is somewhat a concern as we often feel it is. (Perhaps because of using PayPal or because I am out of state the seller ended up not charging me tax after all.)
What can we do to make a safer private larger transaction. I have an anonymous PayPal account set up for a specific mail drop. Can I use two pre paid credit cards to make one purchase? If this was on Amazon can we add two $500 cards to make a $1000 gift card.

I can play around with some prepaid credit cards with a legit PayPal account. Any suggestions?
As I have made it a common practice to make all non tax deductible purchase anonymously, the $500 limit is becoming a concern.