Broadly speaking, Qatar's is a market economy, with some restrictions in place, including for example a pegged currency, restrictions on foreign property ownership, and some import restrictions. Qatar's economy currently doing well, owing almost entirely to strong oil and gas revenues. However, because the riyal is pegged to the US dollar, the government can exert relatively little control over monetary policy. this means they cannot easily contol interest rates. This is why interest rates in Qatar are currently quite low (they should be a bit higher given current rates of economic growth). this, in turn, is driving inflation. the low interest rates mean that borrowing money is quite cheap, so there is a lot of cash sloshing around the system at the moment. this is referred to 'excess liquity'.

there is no income tax for individuals, but corporate tax rates are around 35%. however, there are plenty of tax-breaks that mean corporations can avoid taxes if they meet certain conditions.

hope this helps.