If you're doing a comic thought Image (or, you know, self publishing), one thing that you need to consider is price. The Strange Talent of Luther Strode is going to be 2.99 and issue, which is roughly the industry standard. This is something I had to have a good think about.
There is, for any product, a curve with price and profitability. You'd think that the less something costs, the more it would sell, and that's sometime true. It's also sometimes true that when you raise the prices, sales increase.
I mean, anecdotally, I pay the bills doing really unexciting copywriting, and I get more clients every time I raise my prices. At some point, my fees will cause this to go in the other direction, and somewhere further down the line, raising my prices will start to effect profitability.
So, to get back to comics, if you're charging $3.00 for a comic and you sell 5,000 copies, you gross $15,000. If you charge $3.50, you only need to sell 4,000. At $4.00 you need to sell 3,500. The question is where does maximum profit occur, which is what Marvel was trying to figure out when they went to 3.99 for their comics.
There's no formula for this. You have to consider things like popularity of the creators, for instance. Robert Kirkman could raise his prices by .50 a comic and I would bet everything I have (coincidentally, also worth about .50) that he would make more money.
Likewise, you need to consider the retailer. Price your book too high (relative to a bunch of stuff, but including popularity, genre, and buzz) and they'll be hesitant to order, because that shit isn't returnable.
On the other hand, this goes the other way, too. If your cover price is too low, they aren't making enough money on the book to justify the shelf space. It's tempting to price the first issue low as a loss leader, but looking at the numbers, it doesn't seem to work well in floppies.
(It does seem to do the trick with trades, though.)
A .50 difference is a big per unit difference. That doesn't all come to the creators, but it still represents a significant increase if the sales are the same. It could easily be the difference between a book that's failing and a book that can feed at least one of the creators.
When I was thinking about what to price Luther, I looked at the genres (horror and superhero), our popularity (non existent) the story (weird) and then, well, took a guess. I have a feeling that we'll probably make more money at 2.99 than 3.50, but it's hard to say.