Content matters, but it may depend more on cast.
It also depends on a lot on the producer. Different producer have wildly different price structures.
Christina Carter's web site has very specific, detailed listing of exactly what things cost.
Alex David's site is also pretty specific. So visiting those two would give you a good starting point.
Alex Bettinger charged me based on content, but not how you'd think. His pricing was based on how good he thought my video would sell based on content. So in other words, the more specific I made my script, the more he charged, because he had less control and therefore expected that the video would not sell as well.
In my experience, the biggest element of the price is the talent. Most producers (but not all) charge more for female talent than male (presumably because the female talent get paid more). So a video with a female heroine and a
male villain will often cost less than a female heroine versus a
female villainess.
A video with a solo female would be the cheapest, but this limits you quite a bit in terms of content. I've ordered videos like this, but they are basically femdom PoV where the villainess dominates the viewer.
Minimum cost also depends a lot on length. If you can be happy with a 15 minute video (which to my mind is really just a single scene in a larger story), then it will cost less than an hour-long saga. Most of the customs videos I order are around 30-60 minutes because I like to have a mix of story and sexual content.
Unless you want something very specific and custom-made, costumes probably aren't that big a factor. Most of the studios have a stock of costumes in-house. If you want Christina Carter to do a Wonder Woman video, she's already got the costumes. I don't care much for the stock characters myself, I prefer to make up my own original heroines and costumes, but even then, many studios have a large set of wardrobe item in stock and will put something together for no extra charge. I sent Cali Logan some screen shots that I made using Champions Online and she put the costumers together for free and they were excellent. I did the same with a video for Primal and again, they did a really great job and didn't charge me extra.
Not all studios charge the same, either. There are some studios out there that are very cheap, but I have not had good experiences with these. The video I got wasn't very good.
I assume you probably don't want a solo video, so assuming you need at least two performers, one of them male, if you worked really hard at it, you could probably get someone to make a short (10-15 mins) video for you for under $500.