Man rolls on a gacha machine to receive power-ups, and then goes to another world

Question

Originally, I read this as a light novel, but it is now being made into a manga. In this manga our main protagonist rolls a gacha (like toy vending machine) inside of the back room of some store. There is a clerk there that explains to him that he can roll the gacha for a power and then he will be transported to another world. However, because he rolled the special prize, he is allowed to reroll the power gacha as many times as he wants. I believe he ends up getting either the 99x or 999x (he gets a multiplier to all of his quote-on-quote stats).

Once he decides that he is happy with the power that he has received he is then thrust into the other world. Before leaving the clerk tell him that he is allowed to come back to our world at any time however once he comes a back, he will never be able to return to the fantasy world.

After being transported to the other world he wakes up in a forest. He hears that a carriage is under attack, so he goes to help because he wants to test his newfound power, he got from the gacha. The carriage he ends up saving is a princess's carriage.

Answer 1

I believe this is Kujibiki Tokushou Musou Harem-ken, or 777 Power Harem.

The main character rolls a gacha, gets the grand prize, and goes into the tent behind the table. There he rolls for skills until he gets one he likes, x777 to all abilities, and goes to another world. He quickly finds some beasts attacking a carriage and defeats them. He then learns it was a princess's carriage.