I came across this article on a site for Online Merchants: http://www.auctionbytes.com/cab/abn/y09/m08/i19/s02
It discusses this page on the PayPal web site, a feature called "Guest Checkout": https://cms.paypal.com/cgi-bin/marketingweb?cmd=_render-content&content_ID=marketing_us/eBayFlowCheckout
So, readers could subscribe to Roadfood Insider without opening a PayPal account. It may be necessary to blow away any ebay and PayPal cookies on your machine to make it work, however.
The devil is in the details, however. For one thing, people will have to make sure they do not allow PayPal to store details, thereby effectively opening a PayPal account. I also don't know what questions they will ask. Best bet is to start out by inputting bogus data. If you decide to bail, they will not have any of your personal information. If the questions are not too onerous, blow the cookies away and start over with real details.