Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.) Gleeful Arsonist's first ability resolves before the spell that caused it to trigger
Sacrifice it at the end of combat
After the shipping invoice has been sent out you have 7 days to submit payment, if payment is not made within those 7 days the items will be forfeited
The process has evolved quite a bit since then and now there are plenty of resources, websites, and communities that are so useful I dont know how I ever built decks without them
thats because theyre incredibly rare and, therefore, especially valuable
But, the best avenue to get the cards you want, without spending an absolute fortune, is by purchasing singles, so hopefully this was a handy guide for you