As
@Kieron has already said to you before:
"People who have the time, skill and patience to create buses suitable for Omsi2 are very hard to come by. therefore they are usually tied up in their own projects. People do not undergo these long processes for your pleasure, merely for their own. Therefore no matter how much you offer, people will not make it unless
they want to do it themselves.
I also recommend you don't offer money at all. People will take advantage of you and you will end up paying large sums of money with nothing in return if you chose the wrong sort of person. Most of the good people will not take your money for it and as a result I highly do not recommend giving money away.
Lastly, if you are that disparate for a specific bus, I suggest you try yourself. Trust me, it will be better off doing this than trying your current ploy."