Random Timer is a big problem

[MizArai]

you need enough money to be able to buy two houses - buy a crap one and then to transfer.

This is the best advice you are going to get. The RNG timers suck, but I doubt SE is going to change the way it works. Try to buy a small, less desirable plot in Goblet. This seems to be the least popular housing area and it will probably be easier to snag a house here as opposed to the other housing areas. I think some of the plots go for less than 3mil, which is easy enough to get. This way, when a plot opens up that you do want, you will be able to transfer your FC house right away.

He's on Leviathan, so he's probably trying to buy the crap house now (seems like they're trying to buy anything they find available) and running into this problem.

Telling people to just buy any house that's available on a populated server (where the only available houses are going to be behind the timer) is bad advice. Lots of them (like OP) are already doing that. The timers are ridiculous. I understand why they put them in, though I feel like they weren't needed. It didn't stop flippers like they wanted, it just cut out who can buy flipped houses. All it seems to have done is created plenty of problems for people trying to buy their first house.