President Mikhail S. Gorbachev moved to boost the output of Soviet businesses on Thursday by allowing them - with certain restrictions - to negotiate their own wholesale prices. A presidential decree on prices, released by the Tass news agency, was billed as a step toward a market economy. It was Gorbachev's second decree since the Soviet legislature on Sept. 24 gave him sweeping new powers to rescue the collapsing economy and maintain law and order. Economists have said freeing prices to respond to market forces, rather than having them set by the government, is essential to curing the economy. It is unclear, however, whether the decree frees prices enough to make a difference. The decree says businesses can sign contracts with each other for 1991 using negotiated wholesale prices. But it then adds three restrictions. It says the prices must be based on those outlined by the Council of Ministers in June 1988, that profits over a state-set limit will be taxed and that wholesale prices of some goods will remain fixed. Finance Minister Valentin Pavlov told Soviet television the decree was a compromise but did not say what the differences had been. A correspondent for the nightly TV newscast ``Vremya'' said the decree should put more goods into the stores, by offering price incentives for increased production. Shortages have left many stores nationwide bare of such essential goods as flour, matches, cheese and bread. Pavlov insisted the decree has no direct relation to retail prices and assured viewers that state subsidies will continue. But it appeared stores would have to raise retail prices if they had to pay more to receive wholesale stocks. The finance minister said the decree was necessary so businesses can know now what prices they will be able to charge - and therefore how much product to plan - in 1991. In his first decree, issued one week ago, Gorbachev ordered businesses to fulfill supply contracts and the government to ensure distribution in 1991. He threatened businesses with fines if they did not fulfill supply contracts to government retailers. Many workers and businesses are uncertain how they will fit in the market economy Gorbachev is trying to establish and find it more profitable to trade goods on the black market, rather than distribute them in the established structure. The Supreme Soviet legislature is to choose a plan for switching to a market economy on Oct. 15. The most radical blueprint, written by economist Stanislav Shatalin, calls for junking the central planning system and moving to a market economy within 500 days by selling factories to private owners and breaking up collective farms.