Are there official channels in which the government can get their money from me? Would they send troops to forcibly take the money from me? Does this process differ in the urban centers (think Rome or Alexandria) vs the farming countryside? One last random question, once taxes are collected, where are they stored? Are there official money holding centers?
The head of a Roman family? Or a provincial? A Roman wouldn't have had to pay taxes, Roman citizens were exempt from all taxes except the vectigals, a broad class of duties levied generally on trade. Most Roman citizens would not have paid any taxes at all, except for those few who engaged in some sort of merchant trade and therefore needed to pay vectigal duties. Other than that the only real tax that most Roman citizens paid was the inheritance tax, a subset of the vectigals, which was paid only by a relatively few and only once, when inheritance was passed on--failure to pay the inheritance tax was a big deal, it would get the emperor breathing down your neck. It really depends on what you're looking for--the answer to the question as you've phrased it is that our hypothetical pater familias (what constitutes the height of the Imperial Period exactly?) probably wouldn't pay anything