"I bet" is the present simple form, while "I'll bet" is the contraction of "I will bet" in the future simple form. Both forms express the speaker's willingness to make a wager on the future outcome. The choice between the two may depend on the speaker's preference or the context in which the statement is made.
iGaming involves online betting via electronic means. But if iGaming is making a bet using the internet, then it also falls into the broader concept of gambling, which, in turn, covers a whole range of games, such as casinos, sports betting, sweepstakes, lottery, bingo and card games.