Giving gift in Japan

I need an advice from a local.

I have signed up at the Free Tokyo Guide and my guide seems to be already very helpful. I have read somewhere that Japanese culture highly values gifts. Now I know that the guide is supposed to be free and I would be paying his/here expenses, but am I supposed to be giving her a gift? I was very surprised to know that in Japan there is no tipping for example.
What is a good affordable gift that Japanese people would value from America?

There are licensed professional guides as well as non-licensed volunteer guides. The volunteers are prohibited of receiving money, and they do it for their pure joy of introducing Japan to foreigners.

Gifts giving are done to make yourself comfortable when you are invited by people. You give away gifts because you want the receiving person to feel happy that you cared. Anything from your local place will be welcomed, but I assume sweets are the safest choices.

Promptness is something taken for granted in Japan, so T.I.P. (money to insure promptness) is not necessary. People from toilet cleaners and stock traders put their best efforts, because they take money for their work. In Japan, a toilet cleaner should be a pro toilet cleaner and people would not look down on them.

PS. Offering a drink or a cup of coffee, and inviting him/her to lunch/dinner on your pay as a friend owing help from a friend is a sensible thing to do.