A lot of novices fail to spot the distinction between the open source MySQL and Microsoft's proprietary equivalent, since the acronyms are so similar.
As you have found, it isn't easy to find a good and reasonably priced host with support for the MS way of creating databases and dynamic sites. It's kind of a vicious circle: the additional cost means that open source remains more popular, which means less demand, which means less competition and more cost.
Being an open source user through and through, I have never needed an ASP.net/MS SQL server, but Fast2Host has been recommended to me and it offers full support for ASP.net 3.5 and MS SQL. It looks like it's only £10 p/m, which is in line with Linux servers. It also won its category in the PC Pro Awards thing this year, so obviously has some happy clients. click here Hope that helps you.