You can plant bare root roses during autumn and winter, which is cheaper, or you can plant pot grown specimens September/October or March/April. As for "easy to keep", no roses are easy to keep, they're all high maintenance, needing regular spraying with pesticide/fungicide, regular and correct deadheading, correct pruning at the right time of year, and feeding twice a year with, preferably, a specialist rose food. So pick whatever ones you like, really.