Deckbox is used more as a tool for tracking collections than it is for trading via deckbox
Often also the trade offers I've been offered are not ones I would take (Standard for Eternal or New reprint dropping in value for foil that is increasing in value)
The pricing system is off also on deckbox. Most traders use TCG mid exclusively for trading. Deckbox has incorrect pricing (everything is slightly inflated, almost at an SCG level)
For trading: FB Groups are the best, usually people are verified as legit much easier through mutual friends and/or reputation from community. Strong anti scam presence too, sure some people get ripped off, but majority of users who trade/buy smart dont get screwed.(DONT EVER BUY ANYTHING OVER $20 WITH PAYPAL GIFT - just pay the 3% fee and stop haggling if you want an item)