There are some good deals on rifles...but a Remington 700 is tough to beat. I bought a 700 adk varmint in 243 (they also had then in 223, 22-250 and 308) at Dicks Sporting goods last weekend. They had them on sale for $449. They also sell a version called the 700 long range which comes with a B&C Medalist m40 stock for around $680. That one is available in 25-06. They are pretty decent rifle for the price and they make a great foundation if you decide later you want to build a custom rifle.
As far as caliber goes...I think you can see where my bias is. 243 is not very flashy but they do a great job in the small varmint to big varmint range. If you handload your choices are pretty extensive and components are readily available.