Hi!
I'm jumping over to Deckbox after 5 years on Cardsphere. I completely understand I'm the newb here when it comes to trading and have no issues following the recommended trade process when new. I've been playing MTG on and off since the tail end of Unlimited. This latest span has been since 2016 to current. I mainly play modern, draft and sealed, but have been building a few EDH decks for those occasions.

Cardsphere Profile: https://www.cardsphere.com/user/13866
Discord user: calkno

As for trading, I've typically used #6 coin envelopes with non-machinable stamps. I also have been using ShippingShields over toploaders, but have some toploaders laying around if that is what you prefer. Previously, I've done everything under $30 in a PWE/#6 Coin envelope and anything over in bubble mailer with tracking, but am open to other options.