Obviously price discussion is against the rules
, so we wont be discussing buying X amount a day/week/month/year at X amount per gram/oz/pound.
Its not really a question that could be answered to give a real idea of how much could be spent. You're guess would be as good as anyone Else's. If a person was a multi-millionaire and did nothing but take cocaine
then if they wanted to they could spend multi-millions of euros/pounds/dollars/whatever.
If money was no object then you could also factor in transport, purity, hospital treatments and all sorts of other crap that would be as much a part of the addiction
/use as the cost of the drug
Hundreds of thousands to Millions is probably as close as you will get.
Q. How much could a cocaine addict spend per year on his/her addiction?
A. As much as it takes.