Amazon has CANSHN Clear Cases for iPhone 7/8 Plus, Xs/X on sale for $2.52 each when you apply the corresponding promotion code. Shipping is free with Prime or on orders $25+.
Available Options:
iPhone Xs / X Clear Case $2.52 w/ code 8NP3GXJU
iPhone 7 Plus / 8 Plus Clear Case $2.52 w/ code ZA9DR3E6