Quick information here: One of the trainers in Venam's gym hinted that there are items hidden in the gym. Turns out there's a hidden Ability Capsule in the center room of the gym, sitting comfortably on a rock. Go to Venam's house after beating her, and you can get the TM Poison Sweep from her mom. (Poison Sweep is useful as an anti-fairy move for Axew and a decent STAB move for the Nidorans.) About the Casino in the hotel, the slot machines can actually be played to maximize your chances of getting a 777 (Big Bonus). One of the slot machines have the 7s closer to each other in each row, allowing you to get a maximum of 3 Reg Bonus (777 but with two different colors)! I gambled my way to 10000 coins using that slot machine. Also, in East Gearen's shopping district, there's a chance of a Moomoo Milk Vendor to appear. Excellent recovery for midgame, but you'll be able to farm Moomoo Milk later on, easily. Another vendor that could appear there is a Flute vendor, selling Black and White Flutes for an extremely low price (I think it was 400$). Unfortunately, the Black Flute's effect isn't very potent. For the long run, you'll want to stick to Repels. I think they appear depending on the time of day. Another thing to note is that there's a vendor in the shopping district that sells Lava Cookies, a four times cheaper alternative to the high-end Full Heals. This vendor appears here all the time, so don't worry. Lastly, if you've updated to V8, you'll notice the Pokemon Center outside of Venam's gym got taken down and replaced by a tent. Enter there and meet Radomus Mr. Luck, who offers the service of changing difficulty levels. The first time is free, but I've heard that it's very expensive after the first time.