First you will have to look at your market. How much exposure will ATW give you in your market?
Here's some answers:
Second: what exactly are you trying to achieve with the PFI listings? If you just want your site to be present for branding and overall exposure in ATW, Lycos, etc, I would indeed get good links and wait for free inclusion.
There are some scenarios where PFI makes sense IMO.
- Frequently changing content, time sensitive information
- New site, in need of a jump start
- large db driven sites, with tons of product pages (xml feeds)
If it's a regular small to medium e-com site, I would think about paying only for interior pages, mony makers. The "image" pages, like homepage, about-us, etc I would not pay for. In my experience those pages will get indexed for free sooner or later.