For companies, It's usually 4 four hour events, or 16 hours, to score a 4day badge. I've never seen a gm badge for less than 4 days.
For individuals, who are NOT in a group, you get reimbursed /after/ the show--you purchase your own badge.
For individuals who /are/ in a group, the group is allotted so many badges per events submitted and they can dole them out as they see fit, as far as I'm aware. So if say, some crazy person wants to run enough events for two people, and one person only runs one event, they can both still be assigned badges. Yes, you can be a group with only two people. You for sure want to read up on the gm policy page and such.
Individuals and groups can, if they run enough hours, be reimbursed for hotel if said hotel is in block and if said individuals names are on the bill. Must be submitted by a certain date after the con.
If you're running for the company they have their own requirements for hotel--Catalyst requires 32 hours for a share in a hotel room, and I believe that's the norm.
If you think 32 hours is most of your con, you're right--I've done it. So if you LIKE gm'ing and you want to guarantee you get to play what you want, go for it! You can usually even stipulate when. For instance, I gave my days to Catalyst(8-6 thu, 10-6 fri, 10-6 sat, 10-4 sunday) but got each evening to spend how I wanted. However, as I get older, I'm discovering that's just /slightly/ too much gaming for me, and chances are in 2018 I'll just do the 16 hours for a badge. Maybe. Maybe I'll take a year off! (Who am I kidding, I've gm'd Shadowrun now for like 8 years for them.) But you never know. It does guarantee me my fill, since we have zero groups in the home area who play.
Anyway enough personal stuff...there are some really good short guides on running events, with or without a group, and LOTS of people on here who can help point you in the right direction, if you want to help an already existing group, join a company's volunteers, or strike out on your own.
I don't think VIG passes even get tossed up for sale to the general public anymore--if you want to put your name in the hat for one, send in your information now and cross your fingers.