... and proposes Grid Accounting Services Architecture to m eet them. A number of payment protocols are dis cus s ed and adopted tos uit various trus t relations hips between Grid Service Cons umers and Grid Service Providers . Furth ermore, co-operative and competitive economic models are evaluated with res p ect to exchange of Grids ervices for currencies and an infras tructure named GridBank is des cribed. GridBank allows unambiguous recording of res ource us age ands ervice cos t. Grid Service Consumers use it to gain access to heterogenous computing resources dispersed around the world. Grid Service Providers conduct accountability audits by requesting GridBank statements .