Hi eddie, and welcome to SaleHoo
DM has given you two good options there if you are wanting a free listing platform, but while traffic is growing on those sites don't expect to be flooded with sales at this point in time.
It sounds to me like you are looking for a lot of flexibility in your platform, and that's always a good thing, but it's something you usually only get by developing your own site.
My own personal opinion is that every serious online seller needs to develop their own platform sooner or later, but the big downside to that is being able to generate traffic or no matter what you build, there won't be any sales.
I wouldn't be so quick to forget about eBay, yes they can be a pain in the rear end to deal with, but if you do end up developing your own site, they can also be a fantastic marketing source (if done within their policy guidelines of course) for you to build your own site around.