You're very welcome.

The Ruger 10/22, which lists at $260 to $400 from what I just found on Google from Ruger, has an awesome ecosystem and is relatively easily worked on.

Heck, everything can be bought from someone else (all patents expired by now), and I'm sure there are many alternatives that could get you started.

Also see http://www.gunbroker.com/All/BI.aspx?Keywords=biathlon e.g. there's a Russian rifle which often goes for less than a thousand there. As well as an Anschutz with "Walnut German Stock" for the usual $$$$$$.