It isn't just about being able to delete the spam or not. It is about the time it wastes those who don't want it. At least direct snail mailers have to pay something to annoy you. Spammers can do it virtually for free. We get 100 - 500 a day of spam emails. Yeah, it gets old.
If your product is so good and you know people will want it, why don't you go about it the right way. Instead of taking short cuts that, one, are probably considered spam and two probably break the TOS of EBay, build the site,
SEO/SEM, and watch the traffic that wants your product come. For a potentially faster response use PPC.
Also, since EBay has been successful for you, why are you breaking away from that model?