"If you are a citizen of the United States, you need a passport to fly to or transit through a Canadian airport, but not to enter Canada by land or by boat. You must carry proof of your citizenship, such as a birth certificate, certificate of citizenship or naturalization, or a Certificate of Indian Status, as well as photo identification. If you are a permanent resident of Canada or the U.S, you should bring your Permanent Resident Card with you." Source: Government of Canada
US Passport Information
If you do not have a passport, you can obtain information about the application process at theU.S. Dept. of State. Keep in mind that normal processing
time is 4-6 weeks, so plan accordingly.
Flights and Accommodations
To align with your travel preferences and to give you greatest control over them (in case you have Universal Fan Con flashbacks or watched a Fyre Fest doc), you will make airfare and lodging accommodations on your own.
Keep in mind that Vancouver is expensive, especially during the summer when it’s the most beautiful (and least rainy). July is their high season. This particular weekend has the fewest large conventions in town, so researching the larger convention hotels may be an option as well as vacation rentals, B&Bs and hostels.
Finding a roomie helps to cut costs. A trusted travel agent can best assist you.
Also, remember to check whether costs are listed in Canadian dollars (CAD) or your own currency/US dollars (USD). $100 CAD is currently (as of 3/3/2019) about $75 USD. Exchange rates will fluctuate.
Here is an article that has tips on getting the best currency exchange rates when you travel to another country. Also, remember to alert your credit card company and/or bank that you will be using your card in another country so that your transactions aren't flagged as fraudulent and denied.