I'm assuming you're using this mic, which from what i understand should come with a usb adapter initially. In which case, i'd connect directly into your pc and record, assuming your pc specs are decent and are running low latency drivers like ASIO.

Program wise, Reaper allows for unlimited trial, but asks that you buy the product every time you load up. Give this a try, and afterwards, if you really like the product, you should definitely buy the license. It's only $60, way cheaper than most professional products, and considering that the developers are nice enough to essentially make the software free, the least you could do is show some support.