For testing, basic functionality, and just getting started, I almost always recommend you choose to add a static IP to your internet service. Mine comes with one standard*. It really works surprisingly well, though you won't be able to serve for more than 100 people or so, but like you said, testing, basic functionality, and just learning.
Granted you need to learn a little to setup everything right, but there was a time a friend and I were the primary DNS host for our own domain, ran NetBSD 24x7 with 200+ days uptime, hosted a couple people's email, web and nethack accounts, and this was all on a Mac IIcx, which is all of 16MHz with 8MB of RAM and a NuBUS ethernet card. These days you could do so much more with even less cost. Imagine running a low power machine that's Atom based, and hosts ASP.NET... totally doable. Personally I'd recommend you actually install something "crazy" like the Mono's ASP.NET server on a unix (OpenSolaris or Linux or something) and develop using the mono-project's Mono for Visual Studio.
If you really only need to test and learn, there's always a virtual server you could be running for development only. VMWare player is free, and the mono-project offers an image.
*If you choose to sign up with speakeasy, which you really don't need to just to get a static IP, you can get a discount by saying dlamblin 180380 referred you.