Is $45 asking too much for 3 used ps4 games?

If they’re popular games or newer games and if the disks don’t have any issues, no. If they’re newer games and in good condition honestly you could sell them for a bit more.

Depend on the game and how much they did in sales when first released but it diminish overtime

Depends what kind of games. But most likely too much. I'd give you $10 max for all of them.

EBgames would give you 5$ total

What are the games?

Too much