6 in 1 Sim Card Adapter Kit (Micro, Nano and Standard Sim) Compatible with iPhone X, 8,7 All iPhone Series, Samsung, HTC, and All Other Android Smartphone Devices by Mobi Lock :
Amazon.com: for Replacement 2 x SIM Card Tray for Vivo X9 Accessory (Color : Rose Gold) : Cell Phones & Accessories
Recently bought a Lucky Mobile Multi SIM off their official website for $5.60 (free shipping) and received it (haven't opened it yet). After browsing a bit, I also found it notably cheaper
SpeedTalk Mobile Prepaid SIM Card for Unlocked Smart Cell Phones - Talk & Text 5G 4G LTE Data - 1 Year Service | USA Coverage : Cell Phones & Accessories
Amazon.com: VSVABEFV 4G Mobile WiFi Hotspot Mini LTE Portable Router Multi-Devices Connection Support,Suitable for iPad、Laptop、TV、Cell Phone (Black) : Electronics
Amazon.com: EIOTCLUB Prepaid 4G LTE Cellular SIM Card - No Contract Wireless - USA Compatible with AT&T and T-Mobile Networks for GPS Devices, Security and Hunting Trail Game Cameras - for Data,
Amazon.com New Releases: The best-selling new & future releases in Cell Phone SIM Cards & Prepaid Minutes
Huawei P20 Lite 64GB Midnight Black, Dual Sim, 5.84” inch, 4GB Ram, (GSM Only, No CDMA) Unlocked International Model, No Warranty : Cell Phones & Accessories
USA T-Mobile SIM Card | Carte SIM US États-UNIS | Unlimited High Speed Data/Calls/Texts | Internet Haut Débit/Appels/SMS/Illimités | T Mobile SIM Card US, United States (15 Days) : Amazon.ca: Electronics