Also depends how many cards you want to have and what your definition of a mining rig is- some people might call a rig 2 cards, some 8. Truth is we really can't answer you with such an ambiguous question- you need to give us some basic idea of what you would consider to be a rig, like 6 cards or 8 cards, Nvidia 1000 series or AMD Polaris. The Computer Hardware section and also this section should give you a basic idea of what most rigs look like. If you show us an example we can give you a quote.