eBay has the Unlocked Samsung Galaxy S10+ 128GB GSM Android Smartphone (Black, SM-G975U) for $560 with free shipping. Features Qualcomm Snapdragon 855 2.73GHz octa-core processor, 6.4" 3040x1440 super AMOLED touchscreen LCD, 8GB RAM & 128GB storage, 16MP rear camera & 10MP front camera, Iris scanner & fingerprint reader, 802.11ac wireless & Bluetooth 5.0, Android 9.0 (Pie).
Amazon has the Unlocked Samsung Galaxy A11 32GB Phone (SM-A115UZKAXAA) for $160 with free shipping. List price: $180. Features 6.4" 720x1560 Infinity-O display, 13MP triple-lens front camera, 8MP selfie camera, 4,000mAh battery, 4G LTE capable, Android 10.
Has good Amazon Reviews.