Buying a Russian citizenship legally is possible if you have a cash to put up a business, on the other hand it is not the means to go. CIS citizenship is cannot be consider as good as Europe Union citizenship. Buying of Europe Union is not valid. Putting your documents in the language, you need is arguable point.
As you apply, just write it from your heart, you must have a strong personally case regarding why you want to be a citizen. Frivolous reason is not consider, writing an article on how you have an historical connection that goes way back. You must write on what is true and honest. You must be sincere in the country you are trying to get a citizenship. You need to be patient. It takes years but it is worth to wait. Finally, just remember that in every country in this union is an individual country, in which you apply is significant not only in the union it self but as a whole. Your passport must be given to you by one of member countries