I have stumbled upon two free cloaking scripts. You might want to give them a try before buying a more serious and expensice cloaking tool. I haven’t used them personally so I don’t know how good they are, but if you give them a spin don’t forget to leave a comment here. See? You don’t have to shell out thousands of dollars to cloak a couple pages.

The first one is SmE Cloak Page Lite. Here is an example page, hit refresh to see the links change. If you click a link it changes the small text above the links to include the keywords in the links anchor text.
It doesn’t look half bad for a free script but I don’t think it can compare to commercial scripts’ features. Might be worth to give it a try on some throw away domain.

The second one is KloakIt. This one isn’t totally free but you can use it without buying it and it will put a pop-up for their site. Maybe you could remove the pop-up, but that wouldn’t be nice for the developer. I think it costs around $50 to buy.