I have no problem paying for books and software, but I also like good, free resources when I find them. These are some free star atlases and specialized star charts I have found.
Contact me if there is anything inaccurate here, or if you know of something that should be listed. Some of these links are currently broken. I am hunting down replacements.
Beginner's Star Atlas
This contains six charts with stars to about magtinute 6 and DSOs to about magnitude 9. Each chart has its own object index. They were generated with Skychart / Cartes du Ciel.
constelac
This is a 40 page PDF listing 11000 DSOs with basic data, and small finder charts. It is also cross referenced to Uranometria and Sky Atlas 2000.
Deep Sky Hunter
This has 101 charts, 21 detailed charts, and includes stars down to magnitude 10.2, and DSOs down to 14. This has full sky coverage, and is optimized for A3 paper.
Deep Sky Atlas
This has 80 charts, and includes stars down to magnitude 9.5, and DSOs down to 12.5-13.5. The declination range is 90° N to 58° S, and is optimized for A4 paper.
Deep Sky Objects Illustrated Observing Guide
This is a partially illustrated list of about 7000 deep sky objects from 90° N to 60° S.
Galway Sky Atlas
473 charts, covering stars down to magnitude 10.5 and 10000 objects from the SAC Deep Sky database, generated from Asterope.
JPARSEC
This is a set of charts made with the JPARSEC library. The limiting magnitude is 8.5 for stars, and 12 for deep-sky objects (DSOs). There are 26 charts covering the whole sky, with an object index for each.
Mag-7 Star Atlas Project
This contains 21 charts with stars down to 7.25 and 550 DSO (which are indexed), and provides full sky coverage and constellation lines. The charts themselves were generated with PP3, which is what is used by Wikipedia.
Messier Finder Charts
27 finder charts for the full Messier catalog. Includes constellation lines, and stars down to 7th mangitude.
SAC's 110 Best of the NGC
This is a set of finder charts with Telrad circles for the Saguaro Astronomy Club's list of the 110 best objects from the NGC catalog. The PDF is free for online use, and is $1 if you print it out. Send them the buck.
SFA Star Charts
This is four simple charts with instructions for beginners on how to use them.
Taki's Atlas of Double Stars
This is a specialized atlas with 36 charts containing 2053 double stars, with manual index.
Taki's 6.5 Magnitude Star Atlas
This atlas is optimized for printing on A3 paper, and includes stars to magnitude 6.5 and includes about 500 DSOs. There are two versions, with and without constellation lines.
Taki's 8.5 Magnitude Star Atlas
This includes stars to magnitude 8.5 and provides full sky coverage in 149 charts. It is optimized for A4 paper, and also incudes 2928 DSOs. There are two versions, with and without constellation lines, a manual, and an object index.
TriAtlas
This is a set of three atlases, with stars down to 9, 11, and 13th magnitude. They provide full-sky coverage in 25, 107, and 570 charts each, with contellation lines. There are US and ISO paper versions of each. There were two additional sets available, but these are no longer on the official site.