Answer:
well it depends. usually you go to your local store (pro yugioh players like myself cal them locals for short) and pay a $3-$5 fee to join and you get any 1 pack of you choice (except a gold series pack). and the winner gets some sort of prize whether its a box of 24 packs or maybe just some store credit or maybe a really rare card. some tournament that the better players go to (YCSs or state regional) you pay a $20 and get 5 packs of the latest set that's out. the winner of those get a certain prize as follows:
REGIONAL: get some sort of prize like free packs PLUS an invite to the next YCS (yugioh championship series)
YCS: a paid trip (including accommodations) to the next yugioh world championship qualifier
WORLD CHAMPIONSHIP QUALIFIER: a set of very valuable cards that are very short print and are only given as a prize for the champion PLUS a paid trip (including accommodations) to Tokyo, japan to participate in the yugioh world chamionship!
WORLD CHAMPIONSHIP: i don't know I've never been to one lol sorry i cant help you with that
don't forget the runner-ups get prizes too but im too lazy to mention what they get. they get their invites but there not paid like the winner's prize are.