Many of these sites require you to "verify your download" by entering a credit card or completing a "human verification" survey. These surveys steal your personal information. Within 24 hours, you could see fraudulent charges or your social media accounts being hacked.
Know someone who bought the collection? Lightroom presets and PDF lookbooks are files. Ask a friend if they would share the file with you directly. This is technically piracy if the license is single-user, but between close friends, it is a low-risk, ethical grey area compared to downloading from a public torrent site.
You can view the entire collection in high definition for free on platforms like Pinterest and Instagram. Create a mood board. Follow Randy Dave's official accounts and fan pages. While you can't wear digital photos, you can study the styling, color palettes (usually earth tones, neon accents, and heavy layering), and fit.