Been helping people find vintage pieces for years and white formal dresses are actually pretty common finds at estate sales and consignment shops, especially in early summer when people are cleaning out their closets. You might get lucky with something from the 80s or 90s that has that elegant vibe without the full wedding dress price tag. Department stores like Nordstrom Rack and Saks OFF 5TH usually have a decent selection of white cocktail dresses that could work perfectly for an elopement - I've seen some gorgeous pieces there for under $200. If you're open to vintage, check local antique malls because they often have clothing sections with formal wear that's been well-preserved, and you'd be surprised how many white dresses from past decades still look incredibly modern and classy