If I have a product, what's a good % for affiliates/jvs?

Forgive me if this is addressed somewhere...after two days of searching the forums I haven't yet found a thread, (it's what led me here to begin with) so feel free to redirect me if needed.

I have a product, a physical, tangible CD Rom (video and e-book on disk) that I'm selling for $49.95.

I'm setting up an affiliate program (independent, not through cj or anything like that...I'm small time!) and want to offer a generous commission so that people are interested in being my affiliate, but at the same time, I have real costs: shipping, handling, burning cds, storage, etc...not to mention the production costs of the darn thing, and I'd like to make some money as well....crazy, I know.

In my niche, there are no videos, only ebooks which generally sell for $29, and offer 50-75% commission.

So, what's a decent percentage for an affiliate or jv? From what I've seen so far, it looks like most jvs are 50/50, but affiliates range greatly.

And is that split off of the retail price, or net price after cost?

I know I have the power to set it at whatever I want, but what I really want is for people to sell my stuff, so it has to be appealing.

Likewise, I'm exploring a streaming option...in which case my cost would be nil, (just the increase in bandwith, and tech supprt) and I'd be willing to offer a higher percentage for that...but I haven't set a price-point yet. Is $39.95 reasonable?

Any advice?