GST is simplification of the taxes on the small business and the larger enterprise. It does not directly have impact on consumer. With the simplified taxes, the government is meant to be making things easier on their own end for the taxes. So all the taxes in future are likely to be clubbed into GST. This way small business can focus more on the business aspect instead of small taxes that they have to pay on every transactions.
For consumer, this means less tax burden and sellers are going to be pricing the product and services in more simplified way. Also the amount of local taxes that are being charged will be reduced as well. So we have to take that into consideration.
There is not much impact expected from GST. But you can guess that most of the small business and larger business may hike the prices for their service. So this may push the economy and may increase prices of things around. If this doesn't happen and transition remained smoothly. Then I guess GST turned out to be lot simpler in that case.