This would get you going I bet...
http://www.microcenter.com/product/5...sktop-computer
I just bought a tower specially for recording. Ideally, you want 8gb+ and 3.4ghz processor. For double the price, I got 16gb ram and 4.2ghz processor with 480gb ssd.
With the Acer above, I may use an external hard drive for more storage space, but the solid state drives boot so much faster.