Search new + high quality used tires online. Size 305 30 R21 starting at: $44.59. Tires in stock: 31. Available brands: 3 with 6 models. All season: 6. Summer: 25.. Selling all used tires at discount costs. All used tires go through 2 layers of inspection on specialized equipment. One year warranty + free shipping on all inventory ;) Happy shopping!