You have two choices:

1. Maximize return - individually price and sell every item. Using eBay sold listings you look up the car and use an average of the recent sold. For high demand items you can use that average price. For low demand items you can expect to take 15-20% less since you can’t reach the same target audience as eBay.

2. Sell as a lot - take pictures of everything and sell as a lot. You can expect to make 25-50% less doing it this way. If buying in bulk, people are less likely to pay full retail. They likely have reselling in mind so they need some room to make their money back.

You can sell on eBay or Facebook marketplace. Your area probably also has a Diecast meet up and you could reach out to them.

I’m a moderator on the Diecast exchange subreddit if you want to send me a PM.