Overpaid Legislators, Constituency Projects or Corruption

How much does it cost to maintain a Nigerian legislator? Former president Obasanjo was reported Wednesday August 5, (Sun News) as saying he believes it costs up to 250 million naira.  A whopping figure which if multiplied by the number of legislators in the National Assembly runs into several billions.  Having been president, Obasanjo's comments should not be ignored because he is in a position to know. What is all that money used for?
Obasanjo mentioned constituency projects where the legislators would hire contractors for projects in their various constituencies. Do they really use the money for that? Is there an accounting process instituted for the purpose of monitoring the projects and fund disbursement?
Sun News also quotes the former president as saying: "... we can’t continue to have a National Assembly that is consuming a disproportional part of our resources and then expect that we would be able to make progress. They pass budget that can’t be implemented, because it has to be beefed up to satisfy their whims and caprices. Even what the ministries did not ask for they put it."
While Obasanjo cannot claim to be a saint, a nation run with such flagrant disregard for fiscal responsibility is doomed.  If the legislators actually use the funds for constituency projects, as budgeted, it would serve the various communities well, it would create jobs, infrastructure and other visible development in such communities.  In the US, members of Congress sometimes use what they call earmarks to attract projects and certain infrastructure  to their constituencies.  Even at that, it generates a lot of controversy and political debate but the difference is that those earmarked projects actually get built unlike in Nigeria where the money probably ends up in private coffers. 
Really, how much does it cost to maintain a Nigerian  legislator, from the salaries they approve for themselves to all the allowances, housing, furniture, vehicle, domestic staff, constituency staff and offices etc.?