If you are also lucky enough to load into an instance of the casino with someone that drops a chip bomb, you can follow them around like The Pied Piper of Four Kings for up to 25,000 chips. Every fifteen minutes of game time earns you 250 chips, there is a daily super slot spin that rewards chips (and you can unlock additional spins for progressing through various Tiers) and every so often chips will appear just for you in the casino for you to find.
The real question though is this – is it necessary to buy chips to be able to enjoy The Four Kings? Absolutely not! I found it to be a very generous casino (but don’t say that too loudly whilst you are in there).