Wanted to share a couple (non-membership/non-paid) price-comparison sites I've used.

No account required, no fees. They make money from affiliate/commission links, presumably.

Cell phone and ISP plan comparison: whistleout.com Can choose many details about phone and plan & compare.

Textbook/regular book price comparison: gettextbooks.com Can search by author, ISBN, etc. Sorted by price, including new and used on many sites. Shows shipping cost. I always use this when buying books.