Here is some helpful vocabulary if you’re renting in Japan.
[thank you money / key money] Usually a waste of at least one month’s rent. It’s a gift to the landlord.
[deposit] In some cases it’s three months worth! The deposit is not really a deposit since it’s only partially refundable, even if the place is undamaged. The most returned I’ve heard of was half.
[guarantor] From what I’ve experienced and heard from my Japanese friends, the guarantor must be a Japanese national, over 40, with a stable career and reasonable salary.
Friend A’s father passed away. Despite his mother having money (a lot!), she could not become his guarantor. The friend paid an extra month’s deposit and the agency waived the need of guarantor.
Friend B’s 22 year old girlfriend, a dental assistant, became his guarantor.
All of these factors are highly variable depending on the rental agency you’re using. Some places don’t require all of the above mentioned, and some places are much cheaper than others. Negotiations are possible too, but don’t expect to do this in English or broken Japanese—this is Japan—step your game up, look professional and use keigo (you’ll be surprised how far this will take you).
Personally, I have never experienced any xenophobia or discrimination with the apartment rental agencies, and I have moved four times. I recommend athome because they have a good selection of stylish, modern places for a reasonable price, but their finder’s fee is a bit more than MiniMini.