What feature do you need that JTest is the only one who provides it? (PMD/Checkstyle provide the static analysis functionality). They do have more rules built it, but that's one of the things you are paying for.
As you noted, JTest is not free. If you download from them, you can get a free evaluation license for a short time and with limited features. I asked for a trial license for a week (without having the features stunted) to run against our forum here and received it in exchange for the review. However, coderanch is not a business.