Just spent way too long tracking this down for myself last week, so I feel your pain. The 'Gangsta' situation is kind of a mess – the official English publisher, Seven Seas, stopped printing it and the digital volumes aren't on the usual services like Kindle or ComiXology anymore, at least not all of them. My search led me to a lot of dead ends and sketchy pop-up sites that just weren't worth the risk.
Honestly, your most reliable free option might be checking if your local library's digital service, like Hoopla or OverDrive, has it. Mine didn't, but I've heard some do. Otherwise, it's a series stuck in limbo, which is a real shame because those early volumes have such a distinct, grimy energy. You might stumble across some chapters on sites that host fan scans, but the quality and safety are all over the place.
I ended up buying a couple of the out-of-print physical volumes second-hand, which cost a fortune. The whole thing makes me wish there was a clearer, legal path for accessing older series like this when their licenses get tangled up.