Gonna offer a slightly different angle: sometimes authors run promotions where the first in a series is permanently free. It's not the case for this specific title right now, but signing up for the author's newsletter might net you a different freebie or alert you to a future sale.
For a direct preview of this book, though, retailer sample is the only consistent method I know of.
The anxiety of clicking a pirate link isn't just ethical—it's digital security. Those sites are infamous for hosting malware, aggressive pop-ups, and phishing attempts. Protecting your device and personal data is a practical reason to stick to legal retailers. Amazon, Apple, Kobo, and Google have massive security infrastructures. A random '.top' domain offering free novels does not. The risk of getting a virus or having your data stolen is a tangible cost that outweighs any perceived 'savings' from a pirated book. Legal is safe, in every sense.
I always wonder about the pre-existing friendship with the brother. That relationship is now permanently altered. The brother can never again see his friend as just a friend; he's also his sister's partner, a potential brother-in-law. The wealth adds a weird layer to that. Does the brother now feel he can't be as casual? Does he feel awkward accepting favors?
The original best-friend dynamic, which was presumably based on equality, is now skewed by this new family connection and the ever-present awareness of the financial gulf. The simple, messy friendship gets formalized under the pressure of his status and the new family ties. The relationship between the two men becomes more careful, more polite, maybe even strained. The romantic relationship creates collateral damage in a decades-old friendship, and the money makes everything more delicate.
I don't think there's an official audiobook, unfortunately. Searched high and low after finishing the ebook because I wanted to listen on my commute. Sometimes these indie-published or KU-first titles take a while to get audio versions, if they ever do.
The production costs for audiobooks are pretty significant, so it might not be in the cards. You could always use text-to-speech on your e-reader as a last resort, though it's definitely not the same experience as a professional narrator bringing the characters to life.
I'm going to disagree with the strict publication order purists slightly. If you hate the brother's best friend trope but love enemies-to-lovers, just read 'Rival.' It works as a standalone. You'll miss some nuance, but the core romance is self-contained. Life's too short to force yourself through a trope you dislike on the off-chance the next book is better.
That said, if you're neutral or enjoy both tropes, then 100% go with 'Best Friend' first. You're leaving emotional money on the table if you don't. But for trope-specific readers, sometimes pragmatic entry points are okay. Just know what you're sacrificing.
From a trope-analysis angle, it's textbook 'Overprotective Sibling as Plot Device.' His role isn't meant to be nuanced; it's a boundary. It defines the 'forbidden' in the forbidden romance, raising the stakes by making the love interest's betrayal feel monumental. The portrayal isn't interested in exploring healthy family dynamics. It's about leveraging familial loyalty as an emotional weight. When the best friend crosses that line, it's not just about love—it's about choosing a new allegiance. The brother's protection is the wall that makes the eventual leap so dizzying.