Nope. A user knowingly encouraging you to finish a deal outside of the very platform they're using to sell it to 'avoid fees' is a classic scam tactic, and it's just dishonest even if it's not a scam. If you're willing to do that to save 20%, then be ready to lose 100%.
He proposed me to go outside reverb before I mention any price reduction... My goal is not to do deal outside of reverb.com. The goal is to buy a bass at a good price not above the market price... and in confidence.
That scares off the scammers.