You can't edit your skins directly in Visual Studio, but you can try editing layout.master in a text editor with HTML-specific highlighting to make things a little clearer. For CSS debugging and development, we always recommend using the Firefox Firebug extension to quickly identify where colors and formatting are coming from in your skin. Also be sure to disable CSS caching during skin development to save yourself a lot of grief. Set these keys in user.config, then touch layout.master to reload the settings. Be sure to set them back to true when you're in production:

<add key="CombineCSS" value="false" />
<add key="MinifyCSS" value="false" />
<add key="CacheCssOnServer" value="false"/>
<add key="CacheCssInBrowser" value="false"/>

Keep in mind that it can be a trying and time-consuming experience to create a skin, even when starting from an existing one. When I built my first mojoPortal skin by cloning an existing one, it took me several days of off and on work to get things just the way I wanted them. This was in the days before mojoPortal had added Artisteer support, so I have a little different perspective on the cost of Artisteer: My time spent on that first skin was worth way more than $129, so I think Artisteer is a bargain, since it's the closest thing to a skinning "magic bullet" that you'll find. Once you own it, you can even do fun things like creating seasonal skins, or different skins for each area of your site. Just my $.02, since everyone has a different threshold for purchases.

The other thing you might consider is placing an ad on the Job board here for a skin design. Perhaps an Artisteer owner would be willing to work with you on designing your skin for a price that will work for you.

Jamie