1. A computer program product to provide workflow process models having step-specific cost attributes based on transaction and environment properties, the computer program product comprising: a computer-readable storage device including hardware and having computer-readable program code embodied therewith, the computer-readable program code comprising: computer-readable program code configured to permit editing of a workflow process model, the workflow process model comprising: (i) a plurality of workflow process steps and (ii) branching logic comprising a precondition for traversing at least one workflow process step of the plurality of workflow process steps; computer-readable program code configured to receive a request to assign a step-specific cost attribute to the at least a first workflow process step, wherein the step-specific cost attribute is a predefined function of a plurality of distinct properties including a transaction property and an environment property; and computer-readable program code configured to, when executed by one or more computer processors, assign the step-specific cost attribute to the at least one workflow process step responsive to the request, such that traversal of the first workflow process step by a first transaction invoking the workflow process model results in the step-specific cost attribute being included in a total cost to be charged for executing the first transaction; wherein the workflow process model is executed by an application configured to abort execution of the first workflow process step to comply with a step-specific cost threshold, and to abort execution of the workflow process model to comply with a model-specific cost threshold, wherein at least one of the step-specific cost threshold and the models-specific cost threshold is specified in a service level agreement (SLA).