As mentioned, US LLC fits the bill for both low-cost and tax free. Although make sure you have a clear understanding how income from the US LLC is taxed where you live. It might be different than income from a regular company, in which case you may want to explore for example Isle of Man. Costs are much, much higher than US LLC but the︀ upside is they're more broadly understood entities, and without going into the more irreputable jurisdictions︁ like Seychelles, BVI, and such.
Easy. Never︃ make a profit. 😉