The Galaxy S10e may be the lowest-priced member of the S10 family, but its arguably the most interesting, offering value-for-money unheard of in the Galaxy S range. The international dual-SIM variant of the S10e has been dropping in price, from $600 in April, to $520 in May, and now to $500. If the lack of warranty is a deal-breaker, $550 gets you the US variant from B&H.
This dual-SIM international variant (SM-G970F/DS) of the S10e is powered by an Exynos 9820 instead of the Snapdragon 855, and won't work with Verizon or Sprint. It's being sold by seller never-msrp, who has close to 100k ratings — so you don't need to worry about authenticity.
To sweeten the deal, eBay is currently running a targetted promotion, with 13% eBay Bucks cashback for some accounts (mine happened to receive the promotion email), bringing the effective price down to just $435. To check if you're eligible, search through your emails from the past day or so, or sign into eBay and then click through this link.
If getting the international variant isn't your cup of tea, B&H is currently discounting the North American variants of the S10 family by $200 — so you can get the S10e (SMG970Y) for $550 and use it with all US carriers. Similarly, the S10 is available for $700 and the S10+, for $800.