I don't think you can do this but if you upgrade, they take less. I think you wait until you know your game is going to be successful and then upgrade to keep more of the revenue once you hit a milestone.
Buildbox 1 has not been sold for several years. It would not work for much these days.
Buildbox 2 and 3 are still available however and should suit all of your needs 馃榿 You currently have Buildbox 3. You can find all tutorials at https://www.buildbox.com/tutorials-buildbox3/
There was a forum post by someone who tweaked the camera to make it first person. I think it's possible but will need a lot of work.
Found it: https://www.buildbox.com/forum/index.php?threads/experimenting-with-fps-style-bb3-game.17907/