If you keep your eyes open, you can find good deals on ebooks in the Amazon Kindle store, especially collections that offer a lot of value.
David Feintuch’s Seafort Saga is a series I got into because John J. Reilly reviewed the whole bunch in 1997, a 1950s ish scifi take on the Victorian Navy. The four volumes at the end are on sale for $3.99 USD, a buck a book. [Amazon link]
Tim Zahn’s Dragonback series is one of the best modern juveniles I have had the pleasure of reading. Dragon and Herdsman, Dragon and Judge, and Dragon and Liberator are on sale for $1.99 [Amazon link]
The first collection of Fafhrd and the Gray Mouser is on sale for $3.99 USD [Amazon link]