Retailers are betting that cheap e-readers will help them sell more e-books. That may be true, but readers also have many new options for free or very cheap e-books.

Amazon, which launched a $79 Kindle in late September, announced Thursday that it would offer members of its $79 Amazon Prime service the opportunity to borrow e-books from a catalogue of more than 5,000 titles. Barnes & Noble, which is expected to announce its new lineup of Nook e-readers Nov. 7, may eventually follow suit with a similar subscription-type offering, says Peter Wahlstrom, a senior analyst for Morningstar.

In the meantime, however, readers have no lack of free content, says Alex Goldfayn, a marketing consultant specializing in consumer electronics. Earlier this fall, Amazon joined Barnes & Noble and Sony in making titles available to libraries for consumer borrowing. (Some libraries may soon also let you borrow a Kindle itself, free.) Amazon, Barnes & Noble, Google Books and other sites also have thousands of out-of-copyright titles available for free. Project Gutenberg alone boasts 36,000 free titles. But e-book borrowing options, although growing, still represent just a small slice of available titles, Wahlstrom says. New York Public Library's 76,292 e-book titles, for example, represent a little more than 0.1% of its entire catalog.

E-book lending communities have also multiplied this year -- recent entrants include Lendle, LendInk, BookLending and eBookFling -- to take advantage of consumers' ability to trade purchased e-book titles among friends for short periods. But publishers and manufacturers have the ability to restrict the number of times a book can be borrowed, or prohibit lending a title even once, so don't count on such resources to keep your e-reader full.

Happily, discounts and deals on e-books have also become more common as the category grows. Extrabux.com co-founder Jeff Nobbs says books and e-books tend to get cheaper in general on Saturdays, as more people comparison shop for their weekend reading. Apple offers weekly book specials on iTunes with a rotating selection of titles priced at $3.99 or less, while Amazon's "Kindle Daily Deal" and Barnes & Noble's "Nook Daily Find" each offer one title a day at a deep discount. Thursday's Nook offer, "What Difference Do It Make?," cost $4 instead of the usual $15.99, a 74% discount. Many -- although not all -- general site coupons and coupon codes are eligible on e-books. But while e-books are often cheaper than paper copies, consumers reading through the bestsellers' lists might find the price gap between buying the hardcover and the digital version is slim. Walter Isaacson's Steve Jobs biography costs $17.88 in hardcover on Amazon and $16.99 for a Kindle version. Meanwhile, Amazon Marketplace already has secondhand hardback copies as cheap as $16.40.

Consumers shopping by price on digital books still need to be cautious about which e-reading platform they invest in. Manufacturers want to secure buyers' business long-term, which means that there may be some titles purchased from one e-book purveyor cannot be read on another's devices. Kindle titles, for example, can't be accessed on a Nook, and Amazon won't allow Amazon Prime members to borrow its new selection of free books to read on their cellphone or iPad. "Going forward, it's not going to matter as much," Goldfayn says -- the growing tablet market allows consumers to have an app for each major platform and buy their content from whichever provider is cheapest. Some purveyors, notably Google Books, are also trying to be as platform-neutral as possible so users can access content on any device. The current pricing competition is only the first chapter of what's likely to be a longer price war, he says.