I'm sorry you didn't find a bid that was acceptable to you.
Skinning is a time consuming trial an error process, you introduce styles and images and you test in different browsers. It requires strong knowledge of html and css. It also takes an understanding of what the rendered html structure is and the available css classes that can be used to write scss selectors and apply css style rules. This knowledge can be obtained by viewing the source of the page so anyone who has strong understanding of html can learn how to skin mojoPortal by studying the rendered pages.
However, that does not mean every designer out there is going to be willing to go to that effort. They may get plenty of work that does not require them to learn about any CMS.
If I look at a specific design I may say I can't do it if the design doesn't really lend itself to a CMS. For most of the designs I find on the free design sites I can turn it into a skin in 1 or 2 days. 2 Days at $85/hr is $1360 so that is what I would estimate the job at if I were going to take it on. Maybe my rate seems high but thats because I have the skills and know I can produce the work and if you aren't willing to pay perhaps I have other projects in the wings anyway. Others may have a lower rate but it may take them a week or longer to tweak that skin just right and test it in all the browsers.
so yes, design, html, css, and content management systems are all complex things, but skinning mojoPortal is not more complicated than other cms systems.
An "active market in skins" first requires customers who are willing to pay for the work. If that happens more people with the needed skills will emerge to serve that market. mojoPortal is growing in popularity but we are not yet as popular as some of the content management systems out there so its only natural that we don't yet have a big market for skinning or a lot of designers focusing on mojoPortal skins. When our popularity reaches a certain level I expect this to happen and I think the designers will find that skinning mojoPortal is actually very straightforward compared to some other cms systems. For any single off skin project I don't really think $300-$1000 are unreasonable bids for skilled people. When you see cheaper prices for skins like $50 for a skin bundle its a lot different than 1 skin for 1 customer, they can sell a lot of packages to make up for the cheap price, but custom skinning is a time consuming work.
Best,
Joe