My vehicles won't spawn in/won't move/are invisible!

If you are using Paper, make sure that armor-stands-tick is set to true in your paper.yml file.

My vehicles look like leather boots!

Make sure you've set up your resource pack correctly.

When I try to use /v shop it says there aren't any vehicles for sale!

Make sure that at least one of your vehicles has a price value set that is more than 0. For example:
price: 1000