Like @jbmanning5, I get perfectear plus from signwarehouse.com for $40 for a 300 foot roll, shipped. I’ve used both perfectear and transferrite, I prefer perfectear, but they aren’t that different.
I was also tipped off to this one:
Update: Tape Man Blue’s quality was hit or miss for me, where the tape would unexpectedly separate into multiple layers when unrolling. Maybe I got a bad batch but just something to consider when shopping – sometimes the cheapest option is more expensive in the end.