I mapped the Ping command to mouse5, and when i hold it to get the choice wheel, I get a Lua error from this plugin.

Here's the fix I've applied locally:

BetterVendorPrice/BetterVendorPrice.lua line 248:

if c then

change to

if c and c["GetName"] then

Hope some find that useful!
Cheers!

If it helps, I can put that into a Pull Request, but I think the change is small enough this might be enough to get it in?