This isn't something you can just google. If you were setting up a casino, which tbf would have been more attractive profit wise years ago, you need to start with the risks:
-Regulatory risks; different countries have different regimes; all with different fees/costs
- Competition risk - it's a saturated market still
- Online Marketing - costs related to that, from affiliates through to more traditional forms
- Financing and liquidity risk - how much capital you need to set up and how much revenue to keep the lights on
- If operating across different markets - currency risk changes
Not the answer you're looking for in terms of 'what's the typical set up costs'
You need to ask yourself the question why are you doing this? Do you think there's a quick buck to be made cos i can tell you now if that's what you think you may be in for a shock? Or are you a casino enthusiast who thinks you can create something that the others don't have? Cos in my opinion that's the only situation in which i think it would work.
I think you need cold cash to start and then a knowledge of the sector to start with to even contemplate this - it's quite obvious from playing the amount of casinos that are being set up by advertising companies - look at Nektan; bought over by Grace MEDIA, there's Lindar Media etc.
You also need experience, or support from, folk who know cash flow forecasting, you need to know what markets there are available - the UKGC publishes reports as well as the PLC companies on how many active players there are, their average spends - jump into the annual audit reports for more info
