How to develop a standard method to be used to track & accurate allocate all expenditures related to a project?

SAP. if you are familiar with SAP-PS.MM.FICO , cost control is just easy as in the spreadsheet. BUT this time its controlled real-time. In PS, there is that what we called control avaialability button and once we open that, everything in your PS structure, WBS is cost controlled. Maybe you will find it difficult for now BUT for those familiar with it, this is just very useful in terms of cost control real time expenses. Aother, is PRISM2, the one produced by ARES Management, though i didn't used it yet, but i guess this ones really a good alternative.  There may application avaialble in the market nowadays, but remmeber these are very expensive licenses. The classic approach is through a spreadsheet but be careful input maybe done manually and this prone to mistakes if someone is not very used to it.