Although collecting money through gambling to bahá'í funds is forbidden, in the actual moment nobody can say it is forbidden to the individual (for himself not bahá'í funds). Of course, what is encouraged is that individual gains his life through work in any office or profession, as the excess of gambling is prejudicial since creates vice and bad habits. I think it is permitted when one person go to supermarket and buy products for more than a certain quantity of money, (and sometimes) they give tickets for raffle to win money, cars, appliances, etc.
"As far as individuals are concerned, we have carefully studied the Writings of 'Abdu'l-Bahá and Shoghi Effendi on this point and it is apparent that such subsidiary matters are not recorded in the Holy Texts. The Universal House of Justice is not prepared to decide at this time whether the purchase of lottery tickets should be permitted or prohibited."
(From a letter of the Universal House of Justice to a National Spiritual Assembly, July 4, 1967: Extracts Concerning Gambling, Lotteries and Raffles, a compilation of the Universal House of Justice)
"Although we may have written to you previously commenting on the question as to whether lotteries and betting, such as betting on football games, bingo, etc., are included under the prohibition of gambling, we repeat that this is a matter that is to be considered in detail by the Universal House of Justice. In the meantime, your National Assembly should not make an issue of these matters and should leave it to the consciences of the individual friends who ask to decide for themselves in each case."
(From a letter written of the Universal House of Justice to a National Spiritual Assembly, September 27, 1972: Ibid)