Unbumpable
To be near impossible to swindle, cheat or conned out of something financial. See noun 'bump' (London slang version)
To be savvy enough to avoid paying too much for an item(s) and or service(s)
To be savvy enough to avoid paying too much for an item(s) and or service(s)
They are trying to bump up the prices because we are tourists but they don't know I've been here eight times, I'm unbumpable