i want bustabit.com clone
i am ready to pay 20 to 30$
...
20$ to 30$ won't cover the price for an hour of work for a good programmer. Your best bet is to buy the licence from Ryan, because if someone agrees to do this for you for the price that you are offering (or for free you may say) it may plant a backdoor in the code.
Anyway, even if you get the code, you need to hire someone with programming skils to maintain the website, so maybe it's not such a good ideea to start a business that you don't have the knowledge to maintain.
Right words said only do business in which you are expert or atleast first gain the full knowledge after that start it. Before also some one tried to start the same project but he got loss due to not having full knowledge of the software and through whom it got developed had really backdoor and ruined the project. So it is good to take the license from Ryan so that he will support you fully with full details about the project.