farmer riddle, crack this one.?

a farmer sets off to market with a basket of eggs, he has to cross a toll bridge, but he has no money, so he says to the tollman can I pay you when I sell my eggs at market. Tollman says no, and the farmer says how am I going to pay you. So the Tollman tells him give me half your eggs and half of one, which the farmer does,He arrives at the second toll bridge, and once again the same arrangement is met. He arrives at the third toll bridge, yet again the same arrangement is met. Arriving at the market, the farmer has no eggs left, so how may eggs did he give to each toll man, and he had broken no eggs on the journey to the tollman , how many eggs did the farmer have in his basket, when he started on his journey. Each Tolman had half his eggs + half an egg, what was the lowest number of eggs in his basket.