The best strategy is to deposit $100 and take that $100 and bet it all on red/black on European roulette (only one zero). You can't create multiple accounts in the same casino, and you can get most bonuses only once.
https://www.ww2.site/forum/viewtopic.php?t=94743
https://mmomakemoneyonline.net/threads/jugar-online-tragamonedas-con-bonus-ganar-dinero-con-la-ruleta-online.488718/
http://www.prepody.ru/topic58527.html
https://canadianuniversal.com/stories/showthread.php?tid=50775
https://45.83.123.20/viewtopic.php?t=7676
http://oldsite.giessen46ers.de/fantalk/viewtopic.php?f=9&t=202155
http://bonedryretro.com/forum/viewtopic.php?t=1001715
https://www.ww2.site/forum/viewtopic.php?t=30075
http://forum.bandingklub.cz/viewtopic.php?f=25&t=1230714
http://forum3.bandingklub.cz/viewtopic.php?f=17&t=1418062
https://talk.hyipinvest.net/threads/210857/
http://forum.fretky.cz/info-f46/jak-wygra-du-e-pieni-dze-na-automatach-online-gry-na-automatach-t173888.html
http://forum3.bandingklub.cz/viewtopic.php?f=17&t=1431360
http://forum.bandingklub.cz/viewtopic.php?f=32&t=1221129
https://www.ww2.site/forum/viewtopic.php?p=130487#p130487
http://daveandspencer.com/forums/viewtopic.php?f=5&t=719335