First, what are your intentions for growing Coneflowers (Echinacea or Rudbeckia spp.) indoors? Do you just want to start the seeds early for Spring planting, or are you planning to grow the plants to maturity indoors under artificial lights?
I would strongly recommend the former course over the latter, for a variety of reasons. I would also recommend using a sunny window for seed germination or even overwintering the seeds outdoors in a sheltered spot, as Coneflowers are quite hardy.
As for planting, if you have no in-ground space available, growing the plants outdoors in a large container is quite feasible.
Growing full sun plants under artificial lights requires a significant amount of equipment, effort, expertise, and energy, but it is possible.
In any case, there are many models and brands of artificial light available. You will want to do your own extensive research for this, but be sure to also get a quality light meter, so you can accurately judge how much light the plants are actually receiving.